Sphex opacus Dahlbom, 1845

Buys, Sandor Christiano, 2020, Morphological studies on the last instar larvae of three South American species of Sphecidae (Hymenoptera: Apoidea), Zootaxa 4885 (2), pp. 259-265 : 262-263

Sphex opacus Dahlbom, 1845

Last instar larva

( Figs 7–12 )

Head: Heigth 1.4 mm, width 1.3 mm. Coronal suture short, forming wide notch. Cephalic rugosity absent. Parietal bands brown; 400 mm long, about 15 mm wide. Antennal orbits light brown; subcircular; about 48 mm in diameter. Antennal and frontal concavities brown; clypeal concavity shallower, lighter brown. Coronal and frontal areas without punctures or setae. Epistomal suture indistinct; clypeal area with about 15 punctures; setae absent. Anterior tentorial arms, pleurostoma, and hypostoma brown.

Mouthparts: Labrum bilobed; 280 mm in height, 750 mm wide; inferior and superior margins brown; with about 60 punctures (maximum diameter 8 mm) and 20 basiconic sensillae (4–6 mm in diameter); setae absent. Epipharynx with spines (up to 13 mm long and and 6 mm wide) in marginal, lateral, and median portions, small and scarcer toward the base, spines in median portion facing to base of labrum; sensorial areas with brown dots, with 4/6 basiconic sensillae; marginal band light brown with about seven basiconic sencillae. Mandibles dark brown; 750 mm long; basal portion with six punctures (diameter about 8 mm); setae absent; with four teeth, basal one smaller, teeth gradually larger toward the apex; in inner view mandible is wedge-shaped, inward curved apically, teeth aligned on arc. Maxillae without pigmented areas with few lateral setae (maximum length about 10 mm); maxillary palpi 70 mm long and 55 mm wide; galeae 90 mm long and 65 mm wide; lacinial areas with not curved spines, up to 10 mm long and about 2 mm wide. Labium brown in superior margin and lateral portions; dorsal and marginal portions poorly roughed; labial palpi 75 mm long and 43 mm wide; labial projection of spinneret brown, 580 mm wide, margin with fringe of spines. Peritreme externally without ornamentation. Spines of the opening of the atrium to the sub-atrium cylindrical, with small denticles.

Body: Greyish white. Dorsiventrally flattened; curved. Length 19.5 mm; maximum width 8.5 mm (segment AVI). Dorsal annulets distinct, the posteriorly prominent, not continuous with pleural lobes. Intersegmental lines distinct. Pleural lobes poorly developed on thorax, prominent, joined laterally forming a distinct band continuous with abdomen. Diameter of spiracles: segments TII–TIII = 103 mm; segments AI to AX = 163 mm; spiracular depressions approximately circular, well defined on abdomen, absent on thorax.

Figures

FIGURES 7–12. Larval morphology of Sphex opacus. 7, head, lateral view; 8, head, frontal view (designed from a specimen mounted between glass slides, therefore a little deformed); 9–12, mandible: 9, internal view, 10, external view, 11, inner view; 12, back view).