12 niinois State Lahoratory of Natural History. 



base, and enlarging nearly to the tip, then decreasing. The suc- 

 ceeding segments are short and decrease regularly in diameter. 

 There are peculiar thickened curved hairs on the third, fourth, 

 and fifth joints. A peculiar form of antenna is found in 

 Idiocerus, having comparatively few joints, and the terminal 

 three or four greatly enlarged into a club. 



The mouth parts consist of five pieces; a greatly enlarged 

 labrum, forming a fleshy proboscis surrounding four slender 

 lancet-like processes homologous with the mandibles and 

 maxilla?. 



Thorax. The most anterior segment of the thorax, the 

 prothorax, consists of a large dorsal plate above — the pronotum 

 or disk of the thorax. Beneath (PI. I., Fig. 5), the pleurites and 

 sternum are small, except the episternum, which is often ex- 

 panded into a broad plate which touches the episternum of the 

 other side along the median line. The pronotum covers the edge 

 of the head before and the base of the wings behind. Tt is 

 square or hexagonal in shape, the corners being designated 

 (beginning from before) ats the anterior, posterior, and scu- 

 tellar,— the latter, however, are sometimes wanting. 



The pleurites are well shown in the figure, and the sternum 

 simply forms the bottom of a groove into which the beak is 

 received. With regard to the two remaining segments little 

 need be said. The dorsal surface is covered by the wings 

 (elytra) to which they give rise, with the exception of a large 

 triangular portion called the scutellum. This piece appears to 

 be composed of part of the dorsum of both segments. The 

 portion covered by the wings is sometimes almost membranous, 

 and is never as strong as the rest of the body wall. The pleuri- 

 tes are on the sides; the epipleur* are large and distinct; and 

 the episterna are small. The sterna are transverse and the 

 coxfe extremely large. 



A pair of legs arises from each thoracic segment ( PI. I., Fig. 

 6). They are alike in general appearance, except that the}'^ in- 

 crease greatly in si/efrom before backwards and become propor- 

 tionally more slender and spiny. Each leg consists of (1) a 

 large rounded oval basal joint, the coxa, which is partly received 

 in a hole in the thorax, the coxal cavity; (2) a small, some- 

 what triangular joint, the ti-ochanter; (3) the femur, a long, 



