18 MISC. PUBLICATION 1 47 0, U. S. DEPT. OF AGRICULTURE 



males. Eyes very large, elongate, strongly oblique on inner margins, and closer 

 to each other on the vertex than at the bottom. Pronotum usually wider than 

 long, variable in shape, the base bisinuate, and usually lobed at the middle, with 

 the lobe frequently truncate in front of scutellum. Scutellum small, triangular, 

 xarely long and acuminate toward apex. Elytra about twice as long as wide, 

 rounded or angulated at bases, strongly converging posteriorly, with the sides 

 serrate or entire toward apices. Prosternum broad, flat or convex, the anterior 

 margin frequently with a median lobe. Legs robust ; femora swollen at middle, 

 the anterior pair usually armed with a large tooth ; tarsus compressed, the first 

 segment of posterior one long, and the third segment slightly emarginate, but not 

 armed with long spines at the apex ; tarsal claws simple. 



Head. — In nearly all our species there is a narrow, smooth, longi- 

 tudinal carina on the occiput and vertex, this carina frequently becom- 

 ing bifurcate anteriorly and forming a more or less distinct chevron on 

 the vertex. The term "vertex" is used in the descriptions for the upper 

 part of the front of the head, and "occiput" for the top of the head be- 

 tween the eyes. Frequently there are two small, smooth callosities on 

 the front, but these are variable in the same species and cannot be used 

 in separating allied forms. Sexually the head varies in color, sculp- 

 ture, and density of the pubescence, the front being usually much flat- 

 ter, more densely pubescent, and more finely punctured in the male 

 than in the female, and the head in the male being frequently green, 

 whereas in the female it is aeneous or cupreous. The eyes are usually 

 widely separated on the top, but in a few cases they are nearly con- 

 tiguous. The form of the clypeus is usually more or less uniform in the 

 same species and offers a good character for separating many of the 

 allied forms. It is usually triangularly or arcuately emarginate in 

 front, in some species more widely and deeply than in others, and in 

 some species is slightly variable in shape and depth, so care must be 

 exercised in making use of this character in some species. In a small 

 series of species the clypeus has a notch at the middle, on each side of 

 which is a tooth, which is more or less variable in length in the same 

 species. In floricola the clypeus is transversely truncate or sinuate in 

 front, and in the femorata group (of authors) it is acutely incised at 

 the middle, semicircularly rounded on each side. 



Antenna. — The antenna is either uniform in color or green at base 

 becoming cupreous toward the apex, and frequently the outer portions 

 of the segments are of a slightly different color, but this character is 

 only used in the key when these portions are conspicuously pale yellow, 

 and not merely pale brown. Sexually the antenna varies in color, and 

 is usually more greenish or bronzy green in the male than in the female. 

 It is usually narrowed to the apex ; sometimes the segments are of equal 

 width, but in ludiflcata the apical segments are twice as wide as long, 

 and distinctly wider than the intermediate segments. In a small num- 

 ber of species from the western part of the United States the male has 

 the antenna bipectinate, whereas in the female it is simply serrate. The 

 intermediate segments are either quadrate and compact, or triangular 

 and more or less separated from one another at their outer angles. 



Pronotum. — The disk may be regularly convex, even, more or less 

 uniformly punctured, and without depressions or irregular, smooth ele- 

 vations, or it may be convex (sometimes slightly flattened), uneven, 

 with depressions and irregular, smooth, elevated callosities, in which 

 case the surface is usually irregularly punctured. The lateral margins 

 when seen from above are quite variable in the same species, and are 



