126 GEO. H. HORN, M. D. 



It is, however, in the form of the aaterior tibiae that the greatest dif- 

 ference is observed as is shown in the accompanying figure. From the 

 facies of the species and all the other characters there seems to me no 

 doubt that it should be placed in the pi'esent genus, and the structure of 

 the tibiae of one of the species already quoted seems to indicate the oc- 

 currence of another with the form of tibise of the one now before me. 

 In the present species it will be observed that the submarginal rows of 

 setigerous punctures of the ventral segments 8 — i-o are better marked 

 than in Snoicii. 



One specimen collected by Mr. Morrison iu Arizona. 



CRKMASTOCHILUS Knoch. 



In a review of our species of this genu.s published by me (Proc. Am. 

 Philos. 1879, pp. 382-397 ) there is indicated a peculiar type represented 

 by one species {saucivs) in which the clypeus is strongly longitudinally 

 carinate at middle and the thorax trilobed on the disc. One other spe- 

 cies {planatns) has the clypeus carinate, but with the disc of thorax 

 entire, still another ( Wheelerii) has the disc trilobed, but without clypeal 

 carina. In all the species with widely reflexed clypeus, especially the 

 group below, the surface of the clypeus above is quite smooth and shin- 

 ing. 



The occurrence of two new species enables me to define a small group 

 with the following characters : Mentum plate rather flat, the margins 

 narrowly reflexed, more widely posteriorly, Iiind angle of mentum entire ; 

 head rapidly narrower behind the eyes, the clypeus strongly carinate at 

 middle ; disc of thorax trilobed. 



The species thus included are as follows : 



ibiae of normal form, rather thick, more slender at base: hind tibiae with a small 



tooth at middle. 



Anterior tibiae with the upper tooth near the middle; hind angles of thorax 



small, acute, not everted. sauciiis Lee. 



Anterior tibise with both teeth near the apex ; hind angles of thorax ratlier 



long, slender and everted. spinif'er n. sp. 



ibise broad, laminiform and thin, not much narrower at base, middle and hind 



tibise toothed near the tip. 

 Anterior tibise with both teeth near the apex; hind angles of thorax acute, but 

 short. planipes n. sp. 



C spinif*er n. sp. — Piceous, slightly shining. Head coarsely not densely 

 punctured, the occipital region transversely depressed ; clypeus, viewed from 

 above, nearly semi-circular, margin widely reflexed, at middle very strongly cari- 

 nate, surface smooth. Thorax wider than long, narrower behind, sides arcuate in 

 front, sinuate posteriorly, the hind angles acute and prolonged externally, anterior 



