Enicocephalus flavicollis

Štys, Pavel & Baňař, Petr, 2012, Taxonomy and nomenclature of Enicocephalus flavicollis Westwood — type species of the type genus of the Enicocephalidae (Hemiptera: Heteroptera: Enicocephalomorpha), Zootaxa 3237, pp. 53-68 : 60-64

Enicocephalus flavicollis , larva of 5th instar, description

( Figs. 7–9 )

Material examined. First label: // St Vincent, W.I. //; second label: // 95-206 // [both printed]. Specimen bears third label: // Enicocephalus flavicollis / Westwood, 1837 / larva of fifth instar / P. Štys & P. Baňař det. 2011 // [printed]. Deposited in Department of Entomology, Natural History Museum, London.

Identification by the locality (no other species of Enicocephalidae is known from St. Vincent I.) and by absence of any really contradictory characters against the adults. Colour differences between the larvae and adults are common in the Enicocephalidae (Baňař, Štys, unpubl. observations).

Measurements (in mm). Total body length —2.84. Head (without neck). Total length—0.76, posterior lobe, length—0.24, width—0.44; distance of eye to apex of antennifer—0.17; diatone (maximum width across eyes)— 0.40; dorsal synthlipsis (minimum interocular distance)—0.27; eye, length—0.12; gena, length—0.07, width (minimum)—0.24. Labium. Total length—0.50; segment I, length—0.08; segment II, length—0.09; segment III, length—0.17; segment IV, length—0.16. Antenna. Segment I, length—0.13; segment II, length—0.26, basal width—0.04, distal width—0.07; segment III, length—0.29; segment IV, length—0.33. Pronotum. Total length (median)—0.53; collum, length (median)—0.18, width (maximum)—0.37; midlobe, length (median)—0.40, width (maximum)—0.72. Foreleg. Femur, length—0.62, width (maximum)—0.24; tibia, length—0.58, width (maximum)—0.21.

Coloration. Bicolorous, pale (various shades of yellow) and dark (brown to piceous), but not strongly contrasting except on head capsule.

Head in dorsal view largely brown inclusive postocular part of anterior lobe, postocular constriction and short anterolateral part of the postocular lobe. Lateral parts along anteclypeus, the antennifers, a pair of large subtriangular spots situated mesad to eyes and connected with rudimental ocellar tubercles and lateral sides of posterior lobe of head, and all the ventral surface of head yellowish. Median of postocular lobe yellow.

Antennae and labium yellow, 2nd antennal segment slightly infuscate.

Thorax. Prothorax. Collum yellow; the rest of pronotum brownish yellow, slightly infuscate on the disc; lateral and ventral parts yellow, posterior supracoxale strikingly whitish yellow.

Dorsal parts of pterothorax variegate, yellowish brown to piceous brown, the median yellow. Lateral and ventral areas pale brown to piceous.

Forewing pads mostly piceous (the apical parts nearly blackish), proximal part with a blackish anterolateral streak and yellowish medial streak.

Legs yellowish.

Abdomen. Dorsum (posterad) to forewing lobes: dorsal laterotergites and apex yellowish brown, mediotergites non-contrastingly dark brown. Venter: sterna piceous black, ventral laterotergites contrastingly whitish beige with concolorous extensions onto the sternal area.

Microsculpture. Cuticle with minute, concolorous granules, most of them setigerous. Ventral facies of forefemur with a broad strip of small granules devoid of pilosity in the proximal part, starting at the very basis (distal continuation not observable).

Vestiture. The whole body covered by dense, straight to curve, short pubescence becoming strikingly abundant and curly on body margins (particularly posterior lobe of head, proximolateral margins and apices of forewing lobes, dorsal and ventral abdominal laterotergites and apex of abdomen). Ventral side of head with extremely long setae, mostly longer than the width of eye, straight, oblique and directed posterad on anterior lobe, curved and directed anterad on posterior lobe. Eye bulb with numerous short setae on ventral side and behind the differentiated ommatidial part. Two interommatidial setae. Antennal segments 2–4 with dense, diagonal pilosity, some of the setae on segment 4 more erect and thinner, trichobothrium-like. (Most of the vestiture of legs not observable.) Vestiture of the dorsal facies of forefemur diagonal, straight, with some additional erect trichobothrium-like hairs distally.

Structure. Head. Preocular part of anterior lobe of head short, distance eye - insertion of antenna slightly longer than length of the ocular bulb, genae parallel-sided, shorter than length of the eye bulb (see below). Postocular constriction broad and deep, in lateral view distinct even ventrad to eyes. Posterior lobe of head strongly transverse, ratio of its length to its maximum width 0.54, widest in the middle, lateral margins rounded, median grooved. Ocelli not developed. The eye bulb is a lateral obovate elevation of head, well distinct by its convexity and sharply delimited at its dorsal, anterior and ventral margins by an impressed, linear, C-shaped ocular sulcus. Dorsal and ventral margins of eye bulb are far distant from dorsal and ventral surfaces of head. Only a small anterodorsal part of eye bulb provided with minute, clustered ommatidia, but a 6 (left eye) or 11 (right eye) large, isolated ommatidia fringe the rudiment of eye on its ventral and posterior (left) or also dorsal and anterodorsal side (right). Ecdysial sulcus present on head only, formed by a linearly impresed median of the postocular lobe and Y-shaped linear impression on the anterior one, the armes of the latter running parallel (mesad) to the margins of the brown part of vertex.

Antenna strikingly short, formula IV-II-III-I (lengths of segments II-IV nearly subequal), segments II and III terete (II slightly incrassate distad).

Labium thick and short, formula III-IV-II-I, the second segment strikingly short, with flat dorsal surface; a deep dorsal gulf separating II from I.

Thorax. Collum short, laterally rounded, without ventrolateral tubercles; median indicated by a shallow longitudinal concavity. Midlobe of pronotum (hindlobe absent) with a median, sandglass-shaped impression not reaching its posterior margin and a pair of lateral, arcuate, C-shaped impressions interrupting the posterior margin. Ratio of maximum midlobe width to its median length 1.80.

Forewing pads anapterous (cf. Štys & Šobotník 1999), separated by a sulcus from the mesonotum from their very bases, proximally keeled, distad to the apex of the mesoscutellum contiguous and slightly overlapping.

Legs. Foretibia strikingly widening distad, compressed; ratio of tibia length to its maximum width 2.76. Apicitibial and tarsal armature not studied. Ratio of forefemur length to its maximum width 2.58. Outer claw of foretarsus unrecognizable, probably entirely absent. Claws of mid- and hindlegs isomorphic, apices of tibia with two nearly contiguous combs.

Abdomen with sharply differentiated laterotergites on both its dorsal and ventral sides. Large, subcircular, single opening of the dorsoabdominal gland situated in the middle of mediotergite 4.

Note. Only the 5th instar larva of E. boraceianus has been superficially described ( Wygodzinsky & Schmidt 1991) and attempt of a detailed comparison would be meaningless. The forewing lobes of E. boraceianus are much shorter than in E. flavicollis , not fully reaching posterior margin of segment 2 (exceeding considerably posterior margin of 3), and dorsoabdominal gland opening is very small and situated near the anterior margin of meditergite 4 (large and central in E. flavicollis ).

Figures

FIGURES 6 – 9. Enicocephalus flavicollis Westwood, 1837: 6, male paralectotype; 7 – 9 larva of fifth instar (total length 2.84 mm); 6, head and pronotum, dorsal view; 7, head, dorsal view; 8, total dorsal view with labels under specimen; 9, total lateral view.