THE SLENDER SEED-CORN GROUND-BEETLE. 



15 



Mandibles falcate, slender in front of the retinaculum, apparently smooth; retina- 

 culum much nearer the base than the tip, small, directed slightly backward ; a medium- 

 sized seta on the outer margin of the mandible near the base. 



Maxillae: Maxillary stipes obconical, about 3.6 times longer than wide at its widest 

 point, slightly curved; two large setae on the outer and one on the inner margin near the 

 distal extremity. Outer lobe probably slightly surpassing the first joint of the palpus; 

 joint 1 clavate, with small seta on inner distal margin, about five-eighths as long and 

 one-half as broad as joint 1 of the palpus; joint 2 slender, conical, and fully as long as 

 joint 1. Inner lobe conical, short and inconspicuous, a large seta at its base Pal- 

 pigerous stipes about three-sevenths as long as joint 1 of the palpus, and larger; 

 joint 1 slightly clavate, about three times as long as broad; joint 2 apparently cylindri- 

 cal, not quite half as long as joint 1 and about one-half as broad; joint 3 conical, small, 

 about two-thirds as long as joint 2. 



Labium: Mentum almost quadrate, slightly convex, smooth, much narrower at the 

 proximal than at the distal end, slightly longer than broad at its broadest point; just 



Fig. 9.— The slender seed-corn ground-beetle (Clivina impressifrons): a, Egg; b, larva; c, pupa; d, adult; 

 e, ventral view of larval head; /, ventral view of anal segment; g, antenna. All much enlarged. 

 (Original.) 



below the insertion of the palpi is a large seta; quite hairy except on the ventral sur- 

 face; ventral surface with a very slight groove down the center; on either side of the 

 labium are three or four very large setae, probably arising at its base; joint 1 of the 

 palpus slightly constricted near the base, the distal end the largest, little longer and 

 about the same width as joint 1 of maxillary palpus; joint 2 conical, and nearly as 

 long as the two distal joints of the maxillary palpus; the stipes are slight elevations of 

 the mentum, having no distinct outline. Ligula minute, nearly quadrate, nearly as 

 long as joint 1 of the palpus and bearing two small setae. 



Thorax : Prothorax nearly as long as mesothorax and metathorax combined ; plates 

 much more strongly chitinized; a slight impression on each side near the anterior 

 extremity; two large setae on each lateral surface; one large seta on the lateral surface 

 of the other two thoracic segments; a furrow down the center of each segment (on the 

 dorsum); one pair of thoracic spiracles situated on the mesothorax just anterior to the 

 insertion of the legs. Mesothorax and metathorax about equal in size. 



Legs: Middle pair slightly the largest; coxa very stout, very thick at the base and 

 tapering to about one-third the size at the distal extremity; numerous stout spines on 



