THYCE AND POLYPHYLLA 323 



as that of J. B. Smith in Lachnosterna for instance, it would prob- 

 ably be found that a number of forms thus united subspecifically 

 with others, differ in their complex sexual apparatus to such a degree 

 as to prohibit copulation, even with apparently closely related forms, 

 and we should then be compelled to give them the specific status. 

 All this remains for the careful biologist of the future to work out. 

 Meanwhile, so far as my material indicates, the various species and 

 subspecies are as follows, the characters always taken from the 

 male unless the contrary is stated : 



Anterior tibiae tridentate in both sexes. Kansas and Texas to Arizona. . 2 



Anterior tibiae bidentate in the male except in arguta, tridentate in the 

 female, except in occidentalis, where they are bidentate in that sex 

 exactly as in the male. Atlantic to Pacific and southward to Central 

 America 9 



Anterior tibiae unidentate in the male, bidentate in the female. Florida . 32 



2 Elytra obscurely tricostate; antennae (d 71 ) with the club not much 

 longer than the head. Body in size and form nearly as in variolosa, 

 reddish-brown in color and with sparse depressed yellow hairs; 

 prothorax about twice as wide as long, much rounded on the sides 

 and narrowed both anteriorly and posteriorly; surface moderately 

 densely punctured, channeled, with the sides, dorsal vitta and basal 

 spots more densely pubescent with fine short yellowish hair-like 

 scales; anteriorly there are a few longer hairs and the posterior 

 margin is fringed with not very long hair; head as in hammondi, 

 sparsely clothed with short yellowish hair, with long hair on the 

 vertex, the antennae paler, ferruginous, with the club not much 

 longer than the head; elytra finely rugose, not very shining, with 

 three faint costae, which appear, with the suture, more densely 

 pubescent; abdomen densely clothed with yellowish scale-like hairs, 

 the pectus as usual with long yellow hair; anterior tibiae with three 

 acute teeth. Length 22.5 mm. Mexico (Sonora), Webb. 



*cavifrons Lee. 



Elytra nearly even, sometimes finely and very faintly tricostulate; an- 

 tennal club (of 1 ) always much longer than the head 3 



3 Elytra without trace of solid vittae at any part of the surface, but with 

 lines of sparsely diffused scales 4 



Elytra with lines of sparsely diffused scales throughout, except a more 

 solid short line at base near the humeri, sometimes prolonged nearly 

 throughout the length 5 



Elytra with two or three nearly entire solid though more or less broken 

 vittae of dense, nearly white scales, which however are sometimes very 

 indistinct or more sparsely squamose 6 



4 Last joint of the maxillary palpi slender, slightly arcuate, its outer 

 surface feebly flattened though not at all impressed and slightly 

 rugulose from basal fifth to apical third. Body much larger than 

 the preceding, elongate, subcylindric, pale brownish-testaceous in 

 color and rather shining; head with long coarse yellow hairs and 



