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Strophiona nitens
Classification
Diagnostic Features of Larvae
- Larva. Form much depressed; head very depressed, clothed with a few short, stiff hairs; epistoma very thin, front bearing a transverse suture behind epistoma; labrum roundly trapezoidal, one and one-half times as wide as long; mandible very slender from outer face, dorsal angle scarcely visible; ocelli absent; maxillary palpi slender, last joint very slender, shorter than second; anterior edge of hypostoma broadly fused with ventral mouth-parts. Proeusternum and sternellum shining; mesosternum and metasternum and mesonotum and metanotum dull, velvety asperate; legs very slender, tarsus attenuate. Ampullae dull, finely asperate, marked by two transverse impressed folds, and an anterior one marking off a narrowly fusiform transverse area. Spiracles orbicular, distinctly rimmed. Body hairs coarse, castaneous. Pupa. Form as in adult, covered with very stiff, dark castaneous, subulate setae above clypeus on front and epicranium, two transverse bands on anterior and posterior margin of prothorax, and scattered ones on disc, as also on disc of metanotum, on first six abdominal segments these are coarser than the others; seventh, eighth, and ninth abdominal terga irregularly beset with longer setae, tenth with a bifurcate spine. Adapted from Craighead (1923).
Biology and Economic Importance
- The larval habits of this species form an exception in the genus. It is the only one, so far as known, which attacks living trees. The normal food plant is Castanea, but occasionally it is found in Quercus. The larva bores in the bast fibers of the bark, at the base of the tree or in crotches of limbs where plenty of moisture exists. The burrow is large and irregular, several larvae often extending it from different angles. It is packed with coarse, fibrous frass, which is expelled through a hole in the bark. The pupal cell is formed from an oval rim of this frass. The larval period usually extends over two seasons. The larva pupates in May and June. This species is of much economic importance in relation to the chestnut bark disease. Adapted from Craighead (1923).
Selected References to Larvae Specimens
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