6o6 Journal of Agricultural Research voi. xii, N0.9 



This is the common sweet-potato weevil (PI. 31, A; 32, A, B) with 

 bluish elytra, red thorax and appendages, and black head. The illus- 

 tration of the adult is drawn from a New Orleans specimen. The side 

 view of head and thorax is from a Hawaiian specimen. There is quite 

 a r^nge of difference in measurements of the species but the analysis of 

 these differences is reserved for a more technical paper now in prepara- 

 tion. The immature stages are described from specimens collected at 

 Victoria, Texas. 



Larva. (PI. 34, A-D). — The larva of this species measures from 5 to 8 mm. in 

 length and is white, with light brownish head and darker brown mandibles. The 

 head shield is slightly angulately emarginate behind. From the center of the emar- 

 gination on the median line the epicranial suture passes forward, separating the epi- 

 cranium into two parts; this suture divides behind the frons and forms the two frontal 

 sutures. The frons is subtriangular, emarginate at anterior angles for antennae, 

 and emarginate along epistoma for attachment of clypeus. The median line is im- 

 pressed and darkened. The frons has three pairs of large setae, the posterior pair 

 being closest and the median pair but little more separated. The anterior pair are 

 located very close to the antennal fossae. A tiny pair of setae are located in such a 

 way as almost to form an equilateral triangle with the posterior and median setae. 



The epicranial areas are located on each side of the epicranial suture. Each lobe 

 bears the following setae: One very close to the apex of frons, one slightly posterior 

 to this and farther from the median line, one opposite the middle of the frons, one 

 a little farther from the median line on the same line as the preceding, one toward 

 the base of the frons, one opposite the mid(Jle of the mandible, one opposite the hy{X)S- 

 tomal angle of mandible, one on hypostoma near base of mandible, one opposite 

 but distant from mandible, and three forming a triangle on disc of epicranium. 



The antenna is a fleshy, two-jointed appendage located at the lateral angle of the 

 frons. The mandibles are very bluntly bidentate. Each mandible has a tiny hair 

 about the middle. The clypeus is attached in front of the frons and is broadly trans- 

 verse. It bears on the epistomal margin four tiny hairs. The labrum is not as broad, 

 is rounded in front, and has a row of four setae behind the middle, a seta on each side 

 in front and closer than the outermost setae, and four marginal setae. The maxillae 

 are elongate, terminated by a two-jointed palpus and a setose lacinia. The maxillae 

 are provided with four setae, two near palpus, one at middle, and one at base. The 

 stipes labii is cordate, bearing two-jointed palpi and a single pair of setae. Each 

 lobe of the mentum is provided with two pairs of setae. 



The entire surface of the body is covered with tiny pubescence. 



The prothorax is dorsally not divided but has the praescutal and scutal areas in- 

 dicated by rows of setae. The mesothoracic spiracle is located on a lobe very close 

 to the prothorax. The praescutum of the prothorax and that of the mesothorax are 

 provided with a few small hairs. The scutellum is marked with a row of hairs. 



The first eight abdominal segments are normal and each bears a spiracle. The 

 praescutal area is more or less transversely divided, and its posterior lobe is marked 

 with a few tiny setae. The scutellum is large and prominent and provided with a 

 row of setae. The scutum is only lateral and has just above the spiracle a tiny seta. 

 Each epipleural lobe is provided with a single seta, and each hypopleural lobe with 

 two setse. The coxal lobes of the thorax bear several setae, and those of the abdomen 

 a single seta each. The last two abdominal segments are simple and provided with 

 a number of setae. 



Pupa (PI. 35, E-H). Elongate, about 6 ram. long, white. This pupa is especially 

 characterized by the nongeniculate antennae which lie parallel to the legs. The 

 antennae and two anterior pairs of legs are directed cephalad instead of posteriad. 



