50 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



more distinct spots on the wings, in all which characters it much more closely resem- 

 bles spretus than femur ruh'um. From spreius, again, it is at once distinguished by the 

 smaller size, the more distinct separation of the dark mark running from the eyes on 

 the prothorax, and of the pale line from the base of wings to hind thigh ; and also by 

 the anal joint in the male, tapering more suddenly, and by the two lobes forming the 

 notch being less marked. From both species it is distinguished not only by its smaller 

 size but by the deeper, more livid color of the dark parts, and the paler yellow of the 

 light parts ; the colors thus more strongly contrasting. 



* * * Just as the typical femur-rubrum is at once distinguished from the typical 

 spretus by the characters indicated, so atlanis, though structurally nearer to spretus, is 

 distinguished from it at a glance by its much smaller size and darker, more marbled 

 coloring. The contrast is all the greater in the living specimens of spretus that at all 

 approach it in these respects. 



Measurements of the male. — Length to the tip of the elytra, 0.97, 0.95, 0.98, 0.95, 

 ■0.96, 0.84, 1.05, 0.93. 



C. femur-rubrum, De G. 



This species is also closely allied to spretus and atlanis, and as it has 

 often been described, we will here simply refer to the differences between 

 it and the former of these two (spretus). 



Female. — The only very marked difference between the females is the shorter wings 

 of this species, yet there are other slight variations observable when a large number 

 of specimens are compared, such as the following: The eyes in femur-rulr urn are 

 slightly more prominent; the head, pronotum, and sides of the thorax are usually some 

 shade of olive-bro-vn, varying from pale to almost black ; the black line behind the 

 eyes is quite broad, seldom broken up, and is distinct in the darkest specimens. The 

 humeral (entering) angles of the posterior margin of the pronotum are more rounded 

 and not so sharply defined as in spretus ; the median carina is usually more distinct on 

 the anterior lobes, while the lateral carinal are rather more obtuse and not so well de- 

 fined ; the punctures on the posterior lobe are more distinct. The wings extend but 

 slightly beyond the extremity of the abdomen (see measurements below). In this 

 species and atlanis, the intercalate vein is present in the elytra (notwithstanding the 

 assertion of Stal to the contrary), dimly and imperfectly it is true, but it can be clearly 

 seen for more than half the length of its course; \n spretus it is wanting, its place being 

 marked by the line of union between the two rows of cells. The fuscous spots or dots 

 are not so conspicuous or widely spread over the apical portion of the elytra and the 

 elytra are narrower and straighter. 



As a very general rule, the upper half of the external face or disk of the posterior 

 femora is black or brown, the lower margin and lower half of the inner face bright 

 coral-red ; when these colors are well defined, there is a yellow space or stripe between 

 the red and black ; but these markings are subject to considerable variation, the red 

 sometimes being entirely wanting, the external face dark, and the lower margin yel- 

 low ; sometimes the dark is replaced by a pale olive. The tibiae are most generally 

 bright red, but this character is not without its exceptions. Usually there is a pale 

 ray extending from the base of the wings to the posterior coxa, but is occasionally 

 wanting in dark specimens and is generally absent in spretus. The prosternal spine is 

 not so distinctly quadrate at base as in spretus, transverse, flattened behind, and not 

 regularly conical, but more uniform in size to the broadly-rounded and very blunt 

 apf X. 



Male. — The most constant difference between the species is found in the form of the 

 last ventral segment of the male ; in femur-rudrum this segment, although strongly 

 curved upward as in spretus, is not so distinctly narrowed toward the end but rounded, 

 and instead of being notched at the tip is squarely truncate, presenting a sharp, hori- 

 zontal, and almo t semicircular margin. Below the tip on the posterior face of the 



