POPILLIA. 59 



base, but much narrower there than the elytra at the shoulders, 

 and the base is produced and excised in the middle in front of the 

 scutellum. The elytra are rather short, exposing the pygidium 

 and part of the propygidium, and bear a narrow membranous 

 margin externally. The pygidiuui almost always bears a con- 

 spicuous patch of dense white hairs on each side of the base, the 

 two patches sometimes uniting to form a transverse band. The 

 prosternum is not elevated behind, but the mesosternum forms a 

 process of varying length between the middle coxae. The legs 

 are rather stout, the front tibia armed with two teeth externally, 

 and the tarsi closely articulated and not long. The antennae are 

 short and consist of nine joints. The mandibles are short, rounded 

 externally and blunt or slightly bifid at the tip. The maxilla is 

 armed with five or six very strong sharp teeth. The mentum is 

 long and slightly bilobed in front. All the palpi are short and 

 stout. 



The legs of the male are generally thicker than those of the 

 female, but in the P. cupricollis group the hind legs, and especially 

 the tarsi, are shorter and thicker in the female. The longer claw 

 of the front and middle feet is cleft in the female, but that of the 

 middle foot is entire in the male of most of the species, but 

 cleft in P. nitida, P. schizonycJia, and a few others. The inner 

 front claw is more or less dilated in the male. In a few species 

 the clypeus is straighter at the front edge in that sex. 



In distinguishing the species of this large and difficult genus 

 the number and character of the elytral striae and their intervals 

 is important. For this purpose the dorsal lines and spaces only 

 are counted, that is those lying between the suture and the 

 shoulder prominences (calli), the space adjoining the suture being 

 called the first interval. The second (or subsutural) interval is 

 sometimes similar to the rest and sometimes wide and completely 

 or incompletely divided by a line of punctures along the middle. 



Key to the Species. 



1 (4) Pygidium without hairs. 



2 (3) Clypeus pointed, triangular nasuta, Newm., p. 62. 



3 (2) Clypeus transverse, semicircular . cyanea, Hope, p. 62. 



4 (1) Pygidium decorated with pale 



hairs, generally in two patches. 



5 ('52) Pronotum without hair above. 



6 (49) Elytra without distinct dorsal 



foveae. 



7 (18) Elytra with five equidistant dorsal 



striae. 

 S (17) Ventral segments with double 



rows of hairs. 

 9 (10) Colour uniformly golden-red .... felix, Arrow, p. 63. 



10 (9) Colour not uniform. 



11 (16) Mesosternum produced. 



12 (15) Striae of elytra deep. 



13 (14) Large ; elytral intervals less con- 



vex niargim'collis, Hope, p. 64. 



