Chrysanthrax pennyi Evenhuis, 2017

Evenhuis, Neal L., 2017, A new species of Chrysanthrax Osten Sacken (Diptera: Bombyliidae) from Costa Rica parasitic on an ant lion (Neuroptera: Myrmeleontidae), Zootaxa 4363 (4), pp. 583-588 : 584-587

Chrysanthrax pennyi Evenhuis , n. sp.

( Figs. 1–6)

Diagnosis. Appears closest to C. panamensis Evenhuis & Greathead, 1999 based on the general body coloration and wing infuscation, but can be easily separated from it by the all black scutellum (reddish orange to rust-colored in C. panamensis ) and the all black pilose pleura (yellow pile on pleura in C. panamensis ).

Types. Holotype ♂ from Costa Rica: Limón, Reserva Biológica Hitoy-Cerere, 19 Mar 1991, N.D. Penny, reared from larval Myrmeleon , emerged 7 June 1991 from pupal case. Holotype in California Academy of Sciences .

Descriptions. Adult. Measurements. Body: 7.8 mm. Wing: 8.0 mm. Head. Black; occipital fringe with short black hairs with magenta highlights. Eyes separated at vertex by width of ocellar triangle. Front slightly tumid, black pilose, dense black tomentose immediately above antennae. Face produced, subconical, rounded apically, with black hairs, small spot of yellow ground color at extreme ventrolateral corner. Antenna with scape subcylindrical, flared at mesoapical margin, twice as long as pedicel, with black hairs; pedicel subspherical, with medial ring of black hairs; flagellomere longer than scape and pedicel combined; base subconical, tapering to styliform apical three-fourths, style minute, terminal. Proboscis short, black, not projecting beyond oral margin. Palpi black, with sparse, minute black hairs.

Thorax ( Fig. 1). Mesonotum and scutellum subshining black, with anterior and lateral margins dense black pilose, these hairs with magenta highlights; disc uniformly covered with black tomentum, hairs on disc black, short, minute, not dense, hairs long in prescutellar area. Scutellum with black hairs and tomentum, long hairs along posterior margin. Pleura black above, brown below, black pilose, hairs with magenta highlights. Post alar callus with dense patch of black tomentum and long macrochaetae. Halter stem brown (both knobs broken off and missing).

Legs. Black except hind femora with brown mesoapically; all legs with black hairs and gray to brown tomentum (both midlegs broken off and missing); fore tibia without bristles, with minute thin hairs; all claws of equal size.

Wing ( Fig. 2). Infuscated dark brown to black basally, hyaline apically; veins dark brown to black; basicosta beaked with thick base and pointed apex; cells c, sc, br, bm, and anal and axillary lobes entirely infuscated; cell r1 infuscated at extreme base; cell dm with basal third infuscated; cell m3 infuscated at an angle from cell dm to end of vein CuA at wing margin; remainder of wing hyaline without spots; anal cell open in wing margin by width subequal to r-m crossvein. Alula and calypter fringed with yellowish brown scales.

Abdomen ( Fig. 1). Black, tergites black pilose dorsally, black pilose laterally on tergite I; tergite II with white hairs anterolaterally, black hairs posterolaterally; black tomentum overall (rubbed medially on tergites IV–VI). Venter dark brown, black pilose and tomentose except small patch of white hairs laterally on sternites II and III.

Genitalia not dissected; hypopygium dark brown with long subrectangular epandrium (higher than wide) in lateral view, cercus yellowish brown; gonocoxites dark brown.[Due to recent emergence of the adult at the time of killing, the genitalia had not yet rotated.].

Pupa. Measurements. Overall length: 9.0 mm. Body ( Figs. 3–4 ) generally without hairs dorsally and sparse hairs laterally. Head with cephalic armature ( Fig. 5 ) consisting of paired, apically sclerotized antennal sheaths on each side, each sheath short, pointed medially, other sheaths typically present in other bombyliids (tentorial and labral) absent. Thorax generally bare. Abdomen ( Fig. 4 ) with tergite I without medial spines, with a patch of a few short black hairs at dorsolateral angle another small patch of short hairs laterally; tergites II–VII patch of 5–6 hairs laterally, each segment with apically barbed and sclerotized thorn-like spines medially as follows: tergite II (24 thin); tergite III (24 slightly thicker); tergite IV (16); tergite V (18); tergite VI (12); tergite VII (4 thick and long). Tip of abdomen ( Fig. 6 ) with caudal armature consisting of short paired spines each side, each darkly sclerotized apically.

Remarks. Species in the genus Chrysanthrax are a heterogeneous group possessing a variety of color forms and wing patterns. Most of the recent keys to Villini ( Hall 1970; Hall 1981; Kits et al. 2008; Greathead et al. 2009) used to distinguish various genera use only the following few characters to distinguish Chrysanthrax from other New World Villini : face produced, fore tibiae without bristles, wing infuscation without hyaline spots at crossveins. As a result, it is possible that the wide variety of species that fit into the current concept of “ Chrysanthrax ” may belong to more than one genus (maybe even new genera). The new species described herein, C. pennyi , n. sp., exhibits two suites of characters that do not conform to the typical Chrysanthrax : (1) possessing predominantly black pile on thorax and abdomen (typical Chrysanthrax have predominantly yellow pile) (see also Malloch 1916 about this character in defining the genus); and (2) the pupal cephalic armature is reduced to paired small thorn-like antennal sheaths (the type species of Chrysanthrax has three sets of well-developed long thorns on the headantennal sheaths, tentorial sheaths, and labral sheaths). For now, this species keys to Chrysanthrax and that is where it is placed until further study may show it to belong elsewhere.

The host preference among species in this genus (see Table 1) may prove to be useful in placing species into more than one genus-group. Typical Chrysanthrax (with dark infuscated wings and yellow pile) are secondary parasites of Tiphiidae (Hymenoptera) ; other species (spotted wings and yellow pile) are parasites of Anthophoridae (Hymenoptera) ; while C. pennyi , n. sp. (dark infuscated wings and dark pile) is a parasite of Myrmeleontidae (Neuroptera) .

Species Host

C. cypris (Meigen) Myzinum quinquecintum (Tiphiidae) C. edititia (Say) Anthophora montana (Anthophoridae) C. sp. near edititia Xylocopa mordax ( Anthophoridae ) C. gorgon (Fabricius) Myzinum haemorrhoidalis (Tiphiidae) C. pennyi Evenhuis , n. sp. Myrmeleon sp. ( Myrmeleontidae ) The reduction of cephalic armature and hairs on the pupa is reminiscent of another ant-lion parasite in the Villini , Oestranthrax myrmecaeluri Miksch (Miksch 1993) . It could be that the cocoon of the antlion is soft enough or the soil in which the pupae digs upward to the surface is fine and loose enough that strong spines and armature are not necessary for the bee fly pupae to make its way to the surface for the adult to emerge. Malloch (1916) noted such a correlation in his brief review of pupae of Bombyliidae .

Figures

FIGURE 3. Chrysanthrax pennyi Evenhuis, n. sp., pupal exuvium, lateral view.

FIGURE 4. Chrysanthrax pennyi Evenhuis, n. sp., pupal exuvium, dorsal view.

FIGURES 5–6. Chrysanthrax pennyi Evenhuis, n. sp., pupal armature. 5, cephalic armature, ventral view. 6, oblique view of caudal armature.