 |
Oberea ruficollis
Classification
Diagnostic Features of Larvae
- Larva. Form very elongate, slender, cylindrical; integument smooth, shining, covered with extremely few short, stiff, yellowish-brown hairs. Head thick, conical, sides rapidly converging posteriorly; epistoma narrow, abrupt; clypeus swollen; labrum thin, little wider than long, roundly rectangular, thickly haired; mandible from side, short, triangular, cutting edge oblique often having a very small, acute dorsal tooth; one pair of small distinct ocelli; antenna! ring closed. Ventral mouth-parts thick, rather fleshy; mentum distinct, transverse; maxillary palpi conical, last joint acute, equaling second and shorter than last labial; hypostoma narrow, transverse, anterior edge deeply curved and sunken; gula not distinct. Prothorax. Pronotum very oblique, long and narrow, anteriorly smooth, shining, chitinized, posterior one-half strongly asperate, the asperities flat, reflexed, becoming smaller posteriorly, just inside lateral suture a strong, deep, oblique fovea; presternum narrow, transverse, lateral areas chitinized, extending behind sternellum; eusternum large, roundly trapezoidal; sternellum very narrow. Metanotum. mesosternum, and metasternum very finely asperate. Abdomen elongate, cylindrical; ampullae very narrow, abruptly projecting, having a deep posterior suture and less distinct anterior transverse one meeting distally, surrounding folds very finely asperate; epipleurum strongly protuberant on all segments, tubercles oval, bearing two setae, no chitinous pits; spiracles oblique, lenticular, chitinous rimmed. Pupa. Form like that of adult; a group of short, stiff hairs on disc of pronotum: a v-shaped row of hairs on metanotum; each abdominal tergum bearing a few strong, chitinous-tipped papillae; epipleurum bearing two strong, reflexed, chitinous, tipped papillae. Adapted from Craighead (1923).
Biology and Economic Importance
- The larva feeds in the stems and roots of young living sassafras one-half to two inches in diameter. The eggs are laid at the tip of a small branch just beneath a small portion girdled by the adult. The larvae work downward through the center of the stem to the base and thence often deep into the root. The entire gallery, often several feet long, is kept open, the larvae crawling about in it and when disturbed entering the root. At intervals along the stem the perpendicular holes are opened to the surface through which the frass is exuded. These holes are evident long after as scars on the trees. Pupation takes place near the surface of the ground during May and June. The work of this insect is very abundant through the eastern United States and often causes extensive death of the younger growth. Two or three years are required to complete the development. Adapted from Craighead (1923).
Selected References to Larvae Specimens
| |
