Megischus arizonicus Townes

Aguiar, Alexandre P., 2006, The Stephanidae (Hymenoptera) of Mexico, with description of six new species and key to western Foenatopus Smith, Zootaxa 1186, pp. 1-56 : 21-35

Megischus arizonicus Townes

( Figs 9–16 , 26–34 )

Megischus arizonicus Townes, 1949: 364 , 368; holotype ♀ USNM; Townes, 1951: 90; Carlson, 1979: 741; Gauld, 1995: 184; Aguiar & Johnson, 2003: 470 –472, 474; Aguiar, 2004b: 49.

Morphological variation in females

Body length 27.2–31.4 mm; range of biometric ratios in Table 1. The studied specimens fit well the overall description of M. arizonicus by Townes (1949) and by Aguiar & Johnson (2003), but show some unrecorded variation, summarized as follows. Large size, with fore wing length between 15.0–18.0 mm, contrasting with the 12.5 mm fore wing of the female holotype described by Townes (1949). Mexican female specimens are distinctly darker than US female specimens, showing the head entirely dark brown to black, except for the large yellowish spot on malar space; the propodeum, petiole, and T3–5 (2 nd to 4 th metasomal) may be, entirely or partially, distinctly reddish (190,070,050). The female from Valle de Olivos, representing the northermost record for the species in Mexico, is the most similar to the typical form of the species, but its pronotum anteriorly shows a pair of small carinae curving centrally to generate two longitudinal carinae ( Fig. 29 ), which are in addition to the typically large, oblique carinae of the species. The female from Melaque, in central Mexico, almost at the west coast, also has a somewhat different pronotum, with 4 pairs of anterior carinae ( Fig. 30 ), the first two pairs (anteriorly) small and somewhat hidden, the third and fouth pairs large and conspicuous, curving towards the pronotal fold, the third pair being the largest. In spite of the differences, this specimen matches precisely M. arizonicus in all other taxonomically important features known for the species, and therefore seems to represent only an extreme individual variation.

MALE. The only studied male specimen from Mexico has a body length of about 18.5 mm, and fits well the description of the male of M. arizonicus by Townes (1949), but the colo of pronotum also has a pair of small anterior carinae curving centrally to generate a weak pair of longitudinal carinae, similarly to what was observed for one of the females (see above). In addition, the propodeum, except crenulate sulcus, and the petiole are entirely reddish (240,080,070).

Comments

Similar and clearly related to M. peninsularis sp. n., from which it can be isolated by having the vertex laterally polished ( Fig. 27 ) (vs. extensively areolate/foveolate, with some foveolae extending to temple, Fig. 81 ); interocellar carinae weakly defined, laterally blending with areolation ( Fig. 26 ) (vs. uniform and clearly isolated from areolation, Fig. 79 ); gena ( Fig. 28 ) and mesopleuron ( Fig. 33 ) weakly or sparsely foveolate (vs. coarsely foveolate, Figs 80, 82 ); scutellum lateral area polished, with a narrow submarginal channel ( Fig. 31 ) (vs. taken by deep, straight crenulation, Fig. 83 ); fore and mid coxae mostly polished ( Fig. 32 ) (vs. densely coarsely foveolate, Fig. 84 ); and the petiole somewhat long, on Mexican specimens 5.04–6.07 longer than maximum dorsal width (vs. 4.77–5.29). Fore wing vein 1M at point of connexion with vein 1Cu is somewhat arched, generating a blunt angle (vs. straight, producing a sharp angle), and crossvein 1cu­a meets 1Cu weakly but distinctly beyond point of conexion of 1M/1Cu (vs. nearly opposite). However, the stability of the last two features needs confirmation, since few specimens were examined, and venation in stephanids may vary even between right and left wings of the same specimen.

Distribution Previously known only from the State of Arizona, in the United States; registered here for the first time in Mexico.

Material examined (new records)

Two females and 1 male. ♀ AMNH “ Mexico, Valle de Olivos , Chih., 5500 ft, July 20 1947, D. Rockefeller, Exp. Michener. OSUC22872 .” ♀ EMEC “ Mexico, Jal., 21 Km N Melaque, Fiesta Amer. sign X/16­22/1987, Chemsak & Powell at lites. OSUC22874 .” ♂ CSUC “ Chihuahua, 25 Aug 1986, Kondratieff, Col. Juarez. OSUC22873 .”

Megischus bicolor (Westwood)

( Figs 9–16 , 25 , 35–42 )

Stephanus bicolor Westwood, 1841: 538 , ♀ holotype probably in OXUM; Westwood, 1843: 276 –7; Schletterer, 1889a: 90, 154; Dalla Torre, 1902: 6; Enderlein, 1905: 475; Kieffer, 1908: 4; Elliott, 1922: 716, 732;

Stephanus Sickmanni Schletterer, 1889a: 90 , 152, ♀ holotype ZMHB; Enderlein, 1905: 475; Kieffer, 1908: 4; Elliott, 1922: 716, 727. Synonymized by Carlson (1979).

Megischus floridanus Davis, 1897: 349 , ♀ holotype ANSP; Elliott, 1922: 828; Cresson, 1928: 27. Synonymized by Townes (1949).

Megischus canadensis Davis, 1897: 349 , ♀ holotype ANSP; Elliott, 1922: 827; Cresson, 1928: 27. Synonymized by Townes (1949).

Stephanus Canadensis : Dalla Torre, 1902: 6.

Stephanus Floridanus : Dalla Torre, 1902: 7.

Stephanus sickmannii [sic!]: Dalla Torre, 1902: 9.

Stephanus acutus: Viereck, 1905: 325 , misidentified.

Megischus bicolor: Townes, 1949: 364 , 366; Carlson, 1979: 741; Tobias, 1988: 392; Smith, 1997: 377 –378; Aguiar & Sharkov, 1997: 422; Aguiar & Johnson, 2003: 470, 471, 474–478; Aguiar, 2004b: 50.

Megischus bicolor sickmanni: Townes, 1949: 364 , 367; Townes, 1951: 90.

Megischus bicolor bicolor: Townes, 1949: 364 , 367; Townes, 1951: 90.

Comments

Female body length in Mexican specimens ranges between 13.2–29.3 mm; range of biometric ratios in Table 1. Mexico clearly represents an area of overlap between the predominantly North American M. bicolor (Westwood) and the typically Central American M. niger Smith , generating a morphological continuum between forms of Mexican M. niger and M. bicolor . The separation of these two species for specimens from Mexico will, therefore, be difficult to achieve in some cases. The diagnostic features provided in the key to species are fairly reliable to separate most specimens of these two species, but may be difficult to use with some male specimens; close attention and some training with the key and descriptions will be necessary in such cases. The semiannular laterally strigate, rugulose or rugose ( Fig. 36 ), often with some small foveolae (vs. polished, at least in part, in M. niger , Figs 74, 77, 78 ) is one of the most important diagnostic features for recognizing Mexican specimens of this species.

MALE. Body length from very small to medium, between 8–20 mm. Very similar to the female, except as follows. Smallest specimens (8–11 mm) from Mexico with metapleuron microreticulate in addition to macrosculpture; smallest specimen with pronotum, hind coxa and petiole microreticulate/alutaceous. Mesopleuron alutaceous between foveolae; propodeum more conspicuously alutaceous than on female. The characteristic structure of the pronotum, especially the pair of strongly projecting carinae on colo ( Fig. 38 ), is constant for all specimens, regardless of size. Body color tends to be generally lighter than on female, with brown instead of dark brown, and yellowish brown instead of reddish brown; the contrast between colors is greatest in the smallest specimens ( Fig. 25 ).

Distribution Previously registered from eastern United States and Canada ( Townes, 1949; Aguiar & Johnson, 2003). Here reported for the first time in Mexico, where it is widespread.

Material examined (new records)

19 females, 5 males. 4 ♀♀ CNCI “ Mexico, Q. Roo, X­can, E. Welling , VIII­1963. OSUC21213 , OSUC21217 , OSUC21220 , OSUC21224 .” ♀ EBCC “ Mexico, Jalisco, 4 Km SO de Chamela, 6­VII­1995, F.A. Noguera. OSUC21232 .” ♀ EBCC “ Mexico, Jalisco, Est. Biol. Chamela , 21­VII­1992, F.A. Noguera. OSUC22858 .” ♀ EBCC “ Mexico, Jalisco, Km 6.5, carret 200, 4­VII­1995, R.L. Westcott. OSUC21216 .” ♀ EMEC “ Mexico, Cotaxtla Exp. Sta., Cotaxtla, Ver. , VI­23­1962, D.H. Janzen. OSUC21221 .” ♀ EMEC “ Mexico, Cotaxtla Exp. Sta., Cotaxtla, Ver. , VII­8­1962, D.H. Janzen. OSUC22859 .” ♀ EMEC “ Mexico, Cotaxtla Exp. Sta., Cotaxtla, Ver. , VIII­15­1962, D.H. Janzen. OSUC21223 .” ♀ EMEC “ Mexico, Jalisco, Est. Biol. Chamela , VII/23­31/90, at lights, Chemsak. OSUC21227 .” ♀ EMEC “ Mexico, Simojovel , Chiapas, VII/18­31/58, J.A. Chemsak. OSUC21228 .” ♀ EMUS “ Mexico, Quintana Roo, Felipe Carrillo Pto. , 25 KmW, 19.35N 88.17W, 15­X­86, F.D. Parker. OSUC21219 .” ♀ FSCA “ Mexico, Oaxaca, 23 mi. S. Matias Romero , 3­X­1986, R. Miller & L. Stange. OSUC21229 .” ♀ LACM “ Mexico, Chiapas, 22 Km SW Ocozocoautla , 30 June 1981, E.M. Fisher. OSUC21222 .” ♀ LACM “ Mexico, Q. Roo: X­can, E. Welling , 16­V­1967. OSUC21215 .” ♀ LSUC “ Mexico, Quintana Roo, 5 Km W Chetumal, Hwy. 186, 20­V­1987, D.A. Rider, E.G. & T.J. Riley, collected at mercury vapor and blacklight. OSUC22860 .” ♀ ODAC “ Mexico, Jalisco, Est. Biol. Chamela , 16­X­1996, R.L. Westcott. OSUC21218 .” ♀ UCDC “ Mexico, 23 mi. South Matias Romero , Oaxaca, IV­6­1962, F.D. Parker & L.A. Stange. OSUC21214 .” ♂ EBCC “ Mexico, Jalisco, Chamela , fecha 24­V­85, R. Ayala, s./. OSUC22869 .” ♂ EMUS “ Mexico, Quintana Roo, Felipe Carrillo Pto. , 25 KmW, 19.35N 88.17W, 15­X­86, F.D. Parker. OSUC21231 .” ♂ TAMU “ Mexico, Oaxaca, 10 mi SE Totolapam , VII­20­1987, 4000 ft, R. Wharton. OSUC22866 .” ♂ UGCA “ Mexico, Chiapas, 2.6 Km S La Trinitaria , 20 Oct 1988, R. Turnbow. OSUC22867 .” ♂ UGCA “ Mexico, Yucatan, 3 Km E Chitzen Itza , 23 Oct. 1991, R. Turnbow. OSUC22868 .”

Megischus celaenocephalus Aguiar , sp. n.

( Figs 9–16 , 23 , 43–50 )

Etymology Greek kelainos, black; Greek cephalon, head.

Description

FEMALE. Holotype specimen ( Fig. 23 ). Body length 16.3 mm. Head: Antenna with 31 flagellomeres, f 1 in dorsal view weakly curved outward, slightly thicker than remaining flagellomeres; f2–8 long and narrow, apex somewhat swollen, so that each flagellomere is easily distinguished from one another; f9 intermediate; f10–31 short, solidly fused, hardly distinguished from one another, widening towards f20, then narrowing toward apex, to end in a sharp point. Flagellomeres 1–9 corresponding to about 0.7 of the flagellar length; width change of apical flagellomeres distinct, clearly subdividing antennae in two major sections. Frons and coronal area entirely conspicuously areolate­rugose ( Figs 44, 45 ), the foveolae surface distinctly microareolate ( Figs 44, 45 ); frons with white hairs ( Fig. 44 ), more frequent around antennal foramen and near anterior coronal tubercle. Coronal tubercles well defined, hind tubercles contiguous with each other ( Fig. 45 ). Vertex ( Fig. 43 ) nearly glabrous; three interocellar carinae, polished in between; first carina centrally widely interrupted, present as a large scale at side of each lateral ocellus; second complete, arched; third shortest, somewhat ondulate; area behind posterior ocellus, on anterior 0.4 of vertex, concentrically ondulate­rugose, changing progressively to densely and very finely transversely ondulate­strigulate on most of dorsal area, reaching posterior margin; this pattern changing on temples and dorsal part of gena, to very densely and conspicuously microareolate, matte. Gena prominent, with a central polished callosity ( Fig. 46 ); area of gena below callosity with several white hairs. Occipital carina narrow, sharp; in dorsal view weakly emarginate; in posterior view weakly convergent ventrally, ending far from hypostomal carina, at a distance greater than length of scape.

Mesosoma: Entirely microareolate ( Fig. 48 ; also as in Figs 47, 49, 50 ), with some coarse sculpture, as follows. Pronotum apical margin deeply emarginate, widely U­shaped (as in Fig. 47 ), a narrow, sharp edge distinctly reflexed upwards at about 90 degrees; colo moderately elongate, dorso­centrally approximately flat; anteriorly, on each side, with 4 strong transverse carinae, followed by about 3 others, much weaker, the 2 nd and 4 th (from apex) complete; surface between carinae transversely alutaceous; pronotal fold absent. Semiannular area below pronotal lobe, and femoral impression, longitudinally weakly strigate; microareolae of ventral area distinctly coarser than that of semiannular. Prosternum from microareolate near base of fore coxa to strongly alutaceous at apex. Mesonotum foveolate­rugose, median sulcus weak and narrow, notaulus weakly distinct; axilla foveolate­rugose as mesonotum; scutellum laterally and apically with well­defined, deep foveolae. Mesopleuron with sparse long pale yellow hairs and sparse shallow foveolae; pleural sulcus finely crenulate. Mesopseudosternum weakly but densely alutaceous; discrimen narrow, entirely crenulate. Crenulate sulcus ( Fig. 48 ) deep, well isolated from propodeum; crenulations very strong, parallel­sided. Propodeum ( Fig. 48 ) laterally on anterior 0.7 with sparse shallow foveolae, centro­longitudinally and posteriorly coarsely areolate­rugose; flank without foveolae; spiracular groove distinct, straigth, smooth, ending at crenulate sulcus; spiracular carina straight, sharp, in lateral view distinctly oblique; parapetiolar depression indistinct, entirely taken by propodeal rugosity ( Fig. 48 ). Metapleuron ( Fig. 50 ) centrally, on posterior half, strongly areolaterugose, but this area also taken by very dense pilosity of long, white hairs; otherwise only with microreticulation; ventral margin straight, leaving hind coxa base entirely exposed. Pleuropropodeal fovea indistinct, metapleural foveae deep; interfoveolar area taken by a series of 9 strong crenulations; postfoveolar area with 3 short crenulations. Hind leg, except tarsus, fully microareolate; hind coxa short and swollen, mesally flattened; hind tibia apical 0.6 voluminous, swollen, almost as large as respective femur. Fore wing vein M+Cu with 5 short, erect, translucent, approximately equidistant setae grouped at apex, ending a little behind point of conexion with vein 1M; vein (Rs+M)b about 8.0 times longer than centrally wide; vein 2­1A tubular only on its basal 0.15, otherwise absent, cell 2Cu mostly open posteriorly; veins 2Cua and 2Cub entirely nebulous, but apex of 2Cua and base of 2Cub very large.

Metasoma: Petiole not very long, 5.05 as long as maximum dorsal width; basal 0.1 rugulose, with a few oblique and one longitudinal wrinkle, otherwise entirely microareolate, including ventrally; dorso­apical margin polished; spiracle indicated laterally by a tiny elevation; T3–8 (2 nd –9 th metasomal) taken by very fine and very dense, microscopic sculpture, longitudinally oriented on T3–4, laterally or circularly oriented on T5–6, non­directional on T7–8; in full lateral view, metasoma matte, with refringent texture.

Color: Orange (195,120,040), with head, alinotum and apical half of metasoma black. Antenna from base to flagellomere 6, orange, otherwise dark brown; head black, except basal 0.7 of mandible, area from malar space to hypostomal carina, and central callosity of gena, orange. Mesosoma, including legs, orange, except neck of pronotum dorsally, entire alinotum and crenulate sulcus, dorsal area around petiolar foramen, basal apex of petiole, 2 nd metasomal segment apical 0.2, 4 th segment apical half, and 5 th to 8 th segments entirely, black. Ovipositor reddish brown; ovipositor sheath brown, apical 0.16 black, with subapical yellow band about half as long as black apical portion. Wing membrane light amber, veins brown, except apex of parastigma and base of pterostigma, from pale yellow to translucent.

Morphological variation in females. Range of biometric values in Table 1. Small females (relative to the holotype) tend to be light in color, with black changing to dark brown or orange, particularly head ventrally or posteriorly, and orange changing to yellowish tones.

Comments

Isolated from other Stephanidae , except M. texanus , by the following combination of features: maxillary palp as long as height of head; pronotal fold indistinct, colo approximately continuous with semiannular ( Figs 47, 49 ); semiannular and ventral area of pronotum mostly or entirely microreticulate only ( Figs 47, 49 ); colo anteriorly with a few transverse carinae ( Fig. 47 ); metapleuron centrally with dense tuft of white hairs ( Fig. 50 ), and petiole nearly fully microareolate (as in Fig. 102 ); propodeum conspicuously microreticulate, entirely or at least in between its usually weak macrosculpture ( Fig. 48 ).

Similar and clearly related to M. texanus Cresson , from which it can be separated by having the head dark brown or black ( Fig. 23 ) (vs. yellowish brown or brown in M. texanus ; Figs 97, 99, 101 ); frons inside areolation ( Fig. 44 ), and vertex entirely, densely microreticulate (vs. polished; Figs 98, 100 ); the three anterior coronal tubercles forming an angle distinctly smaller than 90 degrees ( Fig. 45 ) (vs. about 90 degrees; Fig. 98 ).

The same features above will also separate it from some particularly similar color forms of M. texanus ( Fig. 99 ), which, nonetheless, do not show the head mostly black or dark brown (compare to Fig. 23 ). The intercalated pattern of black and orange is typical of M. celaenocephalus , and has not been observed for any other stephanid. The microareolate pattern taking almost the entire body is likewise somewhat characteristic, but also occurs in M. texanus .

61, metapleuron, left; 62, petiole, dorsal. Illustrations not to scale.

MALE. Body length 13.76 mm. Generally very similar to female, except as follows. Temple, gena and frons mostly orange; mesopseudosternum anteriorly and laterally black; mid coxa entirely, hind coxa apex sometimes, hind femur basal half, and hind tibia dilated portion, from weakly to distinctly dark brown.

Distribution Apparently highly endemic, restricted to central Mexico.

Material examined

Four females and 2 males. Holotype ♀ TAMU “ Mexico, Guerrero, 2.1 mi. n. Cacahuamilpa, July 19, 1984, Carroll, Schaffner, Friedlander, OSUC20502 [barcode, plastic].” Complete, well preserved. Paratypes: ♀ ODAC Mexico, Morelos, 2.5 Km N, 4 Km O Huautla, Estación CEAMISH, 9–14/V/1996, Alt. 940 (male), 18º27’.671 N 99º02’.475 O, Trampa Malaise 4, Cols. F.A. Noguera, C.A. Uribe, E. Ramírez, E. González, A. Pérez, S. Zaragoza, B. Rodríguez, M. E. Guardado, OSUC20505.” ♀ TAMU Mexico, Puebla, 13.7 miles southwest Izucar de Matamoros, July 21, 1981, Bogar, Schaffner, Friedlander, OSUC20500.” ♀ UDCC “ Mexico, Yautepec, Mor., VII­13­1963, F.D. Parker & L.A. Stange, OSUC20501.” ♂ CASC “ Mexico, Pue., 9mi. SE. Izucar deMatamoros, 4500’, VI­1­1974, O’Briens & Marshall, OSUC20503.” ♂ CNCI Mexico, Puebla, Tehuitzzingo, 16 Km NW, 7­VIII­83, R. Anderson, OSUC20504,” metasoma beyond petiole missing.

Megischus jaliscoensis Aguiar , sp. n.

( Figs 9–16 , 63–68 )

Etymology Named after the collecting locality of the holotype, Jalisco, Mexico.

Description

FEMALE. Holotype specimen ( Figs 63–68 ). Body length 15.7 mm; biometric ratios in Table 1. Head: Antenna with 34 flagellomeres. Frons areolate­rugose, the carinae strong and sharp, surface inside areolae polished; medially, at level of each antennal foramen, a longitudinal line of few hairs, horizontally decumbent toward each other; along eye margins with short hairs decumbent towards center; latero­ventrally with short hairs decumbent towards clypeus. Coronal area with an oval­elongate, irregular carina encircling central ocellum, and about 8 short carinae radially or longitudinally extending around oval area, towards margin of coronal area. Vertex ( Fig. 63 ) nearly glabrous, a few hairs anteriorly, decumbent towards anterior margin; three distinct sculpture patterns: anteriorly with four arched, regular, concentric, progressively smaller interocellar carinae; laterally broadly areolate­rugose; centro­longitudinally narrowly, transversally, strongly strigate, the sculpture reaching occipital carina centrally ( Fig. 65 ); central impression absent; temple broadly polished ( Fig. 65 ); gena in dorsal view not prominent ( Fig. 63 ), ventral half with large, shallow foveolae with associated hairs, the foveolae closely approximate from each other ( Fig. 64 ). Occipital carina ( Fig. 65 ) as a narrow blade, weakly reflected upwards; very slightly projected dorso­centrally, where it is therefore widest; ending at base of hypostomal carina ( Fig. 64 ); laterally and dorsally with row of equidistant, fine hairs along its length ( Fig. 65 ). Hypostomal area polished, except for some weak transverse striae near base of hypostomal carina.

Mesosoma: Prosternum with weak pre­apical depression; densely, coarsely foveolate. Pronotum ( Fig. 67 ): colo dorsaly widely polished, laterally with 2 pairs of wide, blade­like carinae, the most basal carina strongly curved into pronotal fold, which is very large, deep, its margin strongly reflexed outwards, dorsally with a deep emargination or incision ( Fig. 67 ); a tiny vertical carina inside pronotal fold. Preannular coarsely transversely rugose, the rugosity somewhat straight, polished. Femoral impression wide, surface somewhat irregular, posteriorly covered by dense white pilosity; ventral area gradually shifting from anteriorly obliquely carinate to posteriorly almost longitudinally rugulose and punctate; its posterior 0.8 sparsely pilose. Semiannular mostly densely, coarsely foveolate, except dorso­centrally with strong transverse rugae; each fovea bearing a long, stiff hair; surface in between foveolae polished. Mesoscutum median sulcus indicated by deep, aligned foveolae, notaulus indistinct; lateral lobes coarsely transversely areolate­rugose. Axilla mesally and posteriorly with deep, coalescent foveolae, anteriorly polished. Scutellum mostly polished, marginally with some well defined circular foveolae. Mesepisternum densely, coarsely foveolate very closely spaced, each bearing one long hair; surface in between with punctures and associated fine pilosity. Mesopseudosternum marginally receiving some of the mesepisternum foveolation, otherwise mostly polished; discrimen densely and fully crenulate. Propodeum ( Fig. 68 ) densely foveolate, the foveolae large and sometimes coalescent, generating areolation; a few isolated microfoveolae in between; the foveolae polished inside; sculpture changing posteriorly to about 4 transverse, parallel rugosities near petiolar foramen, continuing laterally inside an elongate but weakly delimited parapetiolar fovea. Spiracular sulcus and carina indicated by a series of aligned areolae (10 mesal plus other 10 small and lateral), extending from base of spiracle to mid of flank, ending near crenulate sulcus; laterally, ventrad of aligned foveolae, broadly polished. Metapleuron centrally coarsely areolate­rugose, with long pilosity associated to the areolae, plus dense short white pilosity in between; ventrally, including post­foveolar area, polished ( Fig. 66 ); interfoveolar area ( Fig. 66 ) fully crenulate. Hind coxa sparsely transverse­rugose, the rugae with small elevations in some points, each bearing one long hair on its posterior face, the hairs strongly inclined towards apex; mesally, on central 0.4, flattened, with dense patch of ventrally decumbent short hairs. Hind femur and compressed half of hind tibia polished, dilated apical half finely alutaceous; femur and tibia covered with long, sparse, stiff pilosity, inclined about 45 degrees towards apex; hind tibia posteriorly strongly pinched on basal 0.5, generating a posterior carina or edge and a central, large, somewhat circular, transverse compression; basal half ventrally with a sharp edge, ending where the dilated portion begins.

Metasoma: Petiole densely transversely strigate. T3 (2 nd metasomal) apparently polished, but from basally faintly to apically distinctly longitudinally microreticulate, the individual reticles hexagonal; T4–8 finely transversely alutaceous; T9 microreticulate. Pygidial sulcus widely V­shaped, forming an equilateral triangle, also a short longitudinal depression extending from its base over T9, generating a Y­shape; pygidium apical margin widely polished, isolated from small basal portion by a row of long, translucent hairs; area behind hairs somewhat irregular, alutaceous.

Color. Antenna changing progressively from basally yellowish brown (209,160,081) to apically dark brown. Body mostly brown with light reddish tint (158,087,067); fore and mid legs, and hind tarsus, with orange tone (184,112,029); metasoma, except petiole, darkest (109,056,032). Wing membrane pale amber (244,246,218), veins brown (127,096,073).

MALE. Unknown.

Comments

This species seems to represent an intermediate form between M. anaxeus sp. n. and M. arizonicus Townes , and is separated from both these species by several features. However, it apparently lacks a defining autapomorphy, except perhaps for T3 (2 nd metasomal tergite) with weak, longitudinal alutaceous pattern. A similar pattern is also observed in species of the distantly related M. bicolor group. Megischus jaliscoensis sp. n. is further separated from M. anaxeus sp. n. by the same set of features that isolates the latter species from M. arizonicus (listed under “Comments” for M. anaxeus ). It is further separated from M. arizonicus by having the maximum head width at level of gena distinctly shorter than the maximum head width at eye level ( Fig. 63 ), with a ratio of about 0.9 (vs. slightly greater than at eye level, as in Fig. 26 , with a ratio of about 1.02; although small, the difference is consistent and perceptible); spiracular groove and carina inconspicuous, overtaken by a series of narrow, transverse areolations from spiracle to crenulate sulcus (vs. spiracular carina more distinct and straight, spiracular groove indistinct, taken by overall propodeal sculpture in M. arizonicus ); metapleuron centrally with short dense pilosity between sparse long hairs, as in Fig. 61 (vs. without short dense pilosity, Fig. 34 ); hind femur with apical tooth longer than central tooth (vs. shorter); and petiole in lateral view slender, 11 times longer than its maximum height, reached at the apical 0.3 (vs. petiole stout, about 6 times longer than maximum height, reached at apical 0.4).

Material examined Holotype ♀ EBCC “ Mexico, Jalisco, Chamela , FANM 410 , 22­IX­1986, F.A. Noguera. OSUC22898 .” Ovipositor valves missing; otherwise complete, well preserved.

Figures

FIGURES 9–16. Values of morphometric ratios for all examined female specimens of all species of Mexican Megischus. Species grouped in the Y­axis according to their order of appearance and morphological similarity in the key to species; key structure also indicated by the dendrogram applied to Y­axis of Figure 9. Legends for all graphs: an, M. anaxeus, sp. n.; az, M. arizonicus; bc, M. bicolor; cl, M. celaenocephalus, sp. n.; jc, M. jaliscoensis, sp. n.; ml, M. melanogladius, sp. n.; mx, M. mexicanus, sp. n.; ng, M. niger; pn, M. peninsularis, sp. n.; tx, M. texanus. For ratio abbreviations, see text.

FIGURES 26–34. Megischus arizonicus Townes, ♀. 26, head, dorsal; 27, head, dorso­lateral; 28, gena, left; 29, pronotum and anterior part of mesonotum, dorsal; 30, pronotum, anterior half, dorsal; 31, axilla, scutellum and crenulate sulcus, dorsal; 32, mid left coxa; 33, mesopleuron, propodeum (part) and metapleuron (part), left; 34, interfoveolar area, propodeum and metapleuron, left. Illustrations not to scale.

FIGURES 79–86. Megischus peninsularis, sp. n., holotype ♀. 79, head, dorsal; 80, head, dorsolateral, left; 81, head, latero­ventral, slightly shifted posteriorly to show gena; 82, posterior half of pronotum, mesopleuron, and part of propodeum + metapleuron, left; 83, axilla, scutellum and crenulate sulcus, shifted to the left; 84, post­foveolar area and mid coxa, left; 85, propodeum + metapleuron, dorsal; 86, same, detail of left side. Illustrations not to scale.

FIGURES 23–25. Mexican representatives of Megischus Brullé. 23, M. celaenocephalus, sp. n., holotype ♀, dorsal view; 24, M. mexicanus sp. n., holotype ♀, habitus; 25, M. bicolor (Westwood), ♂, habitus. Illustrations not to scale.

FIGURES 35–42. Megischus bicolor (Westwood), ♀. 35, head, dorsal; 36, pronotum and prosternum, left; 37, apex of hind left tibia and its respective tarsus, lateral; 38, pronotum and anterior part of mesonotum, dorsal; 39, mesopleuron, left; 40, apex of petiole and tergites 3–4, dorsal; 41, intercoxal space between hind coxa, posterior view; 42, propodeum, dorso­lateral, left. Illustrations not to scale.

FIGURES 73–78. Megischus niger Smith, ♀. 73, pronotum and anterior part of mesonotum, dorsal; 74, pro­ and mesothorax, left; 75, apex of petiole and tergites 3–4, dorsal; 76, apex of hind left tibia and its respective tarsus, lateral; 77, pronotum and prosternum (detached), left; 78, posterior half of pronotum, mesopleuron, and part of propodeum + metapleuron, left. Illustrations not to scale.

FIGURES 43–50. Megischus celaenocephalus, sp. n., ♀. 43, head, dorsal, holotype; 44, detail of frons, left, holotype; 45, coronal area and respective aterior ocellum, dorsal view, holotype; 46, head, left, paratype OSUC20500; 47, pronotum and anterior part of mesonotum, dorsal, paratype OSUC20501; 48, propodeum and crenulate sulcus, dorsal, holotype; 49, pronotum, left, paratype OSUC20501; 50, metalpleuron + propodeum, left, paratype OSUC20500. Illustrations not to scale.

FIGURES 96–102. Megischus texanus Cresson. 96, head, dorsal, ♀; 97, light colored form, habitus, ♂; 98, coronal area and respective anterior ocellum, dorsal, ♀; 99, form with darkened mesonotum and apex of metasoma, full dorsal view, ♀; 100, detail of frons, left, ♀; 101, habitus, ♀; 102, petiole, dorsal, ♀. Illustrations not to scale.

FIGURES 63–68. Megischus jaliscoensis, sp. n., holotype ♀. 63, head, dorsal; 64, head, lateroventral, slightly shifted posteriorly to show gena; 65, head, dorsal, detail of posterior margin; 66, interfoveolar area, between mesopleuron and metapleuron; 67, pronotum and anterior part of mesonotum, dorsal; 68, propodeum, dorsal. Illustrations not to scale.

FIGURES 60–62. Megischus anaxeus, sp. n., holotype ♀. 60, propodeum + metapleuron, dorsal;