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Megacyllene acuta
Classification
Diagnostic Features of Larvae
- Mature larva. Head subtrapezoidal, with sides almost straight, slightly diverging posteriorly. Gena somewhat shouldered, pale, smooth, bearing several short pale setae. Frons testaceous, with front margin rather broadly ferruginous. Mouthframe rather strongly sclerotized, ferruginous; completely sclerotized beneath antennae, but not enclosing ocellus. Antenna with segment 3 cylindrical, about four times as long as broad and about half as long as segment 2; supplementary process very short. Labrum semicircular, fringed with fine silky setae. Three pairs of subcontiguous ocelli present. Hypostoma broadly ferruginous and strongly transversely striate; sutures slightly curved, ferruginous. Gula rather broad, distinctly raised. Maxilla with segment 3 of palp slightly shorter than segment 2; dorso-external process of palpifer much shorter than segment 3 of palp. Labial palpi with segment 2 much shorter than segment 1. Prothorax with pronotum orange-testaceous anteriorly; longitudinally rugose, becoming micro-granulate and glabrous posteriorly; median cleavage line rather feebly impressed. Eusternum glabrous except medially where it is sparsely setose. Abdomen with dorsal ampullae dull, extremely finely micro-granulate, milky white. Anal lobes sparsely setose. Pleural discs indistinct. Legs very small, 2-segmented, almost as long as second and third segments of maxillary palp. Spiracles with peritreme rather broadly oval, thin and without marginal chambers. Length up to 25 mm; maximum breadth (at prothorax) 8 mm.
Pupa. Head with vertex visible from above, smooth; front transversely striate medially, glabrous. Antennae short, extending as far as abdominal segment 2, where they terminate above elytra. Eyes moderately convex, glabrous. Labrum glabrous. Pronotum slightly transverse, with sides moderately rounded and smooth; anterolateral areas bearing a few scattered spinules. Mesonotum and metanotum with a few scattered setae; scutellar groove distinct, transversely striate. Elytra and wings extending to abdominal segment 3. Abdomen with tergites 2-6 each with a transverse row of straight spines anterior to which are several irregularly placed spines. Tergite 7 with three pairs of inwardly curved spines anterior to the six larger anteriorly curved spines across posterior margin, the two anterior pairs being appreciably smaller than remaining pair. Tergite 8 bearing four stout inwardly curved spines. Segment 9 retracted in segment 8. Sternites with a few minute setae sublaterally. Pleura moderately protuberant, glabrous. Legs with hind femora extending as far as abdominal segment 4 and placed parallel to longitudinal ax.is of body. Functional spiracles present on abdominal segments 1-5, those on segments 6-8 being closed and probably non-functional; peritreme rather narrowly oval and not appreciably raised above general level of cuticle. Length up to 21 mm; maximum breadth 8 mm. Adapted from Duffy (1960).
Biology and Economic Importance
- Members of this tribe are known from various host plant families and several genera (e.g., Chlorophorus, Xylotrechus) are considered economically important. Species of this tribe are potentially invasive outside their native range. More information is available at the CAPS website.
Selected References to Larvae Specimens
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