280 GEO. H. HORN, M. D. 



C. inaequalis, Horn. — I consider this in the same manner a dimor- 

 phic female of seminiger, Lee. 



HYDATICUS. 



//. modestus, Slip., cinctipennis, Aube, americanus, Slip. — In the 

 separation of these three species from stagnalis, Fab., I can not agree 

 with Dr. Sharp. The only differences are in the color of the upper sur- 

 face. These variations seem to run gradually from one style to another. 

 The form in which the elytra (except the sides) are black is the most 

 common. A second variation occurs with a subbasal yellow transverse 

 band of variable distinctness. The band then becomes pectinate pos- 

 teriorly, and we have the vittate varieties thus gradually formed. 



Ail I, I IS. 



A. semisalcatus, Aube. — Crotch was entirely correct in noting smooth 

 females for this species. I have doubts whether this species should be 

 considered distinct from fraternus, Harr. In studying our large series I 

 find the females in the Eastern Atlantic region to be equally divided 

 between the smooth and the sulcate forms. The sulci extend very little 

 in front of the middle of the elytra. As we go west the sulci become 

 gradually longer, so that the Oregon and Alaskan specimens are sulcate 

 very nearly to the base. Smooth females become rare as we go west- 

 ward. I think our collections demonstrate the identity of these two 

 species. 



In a recent letter Dr. Sharp holds that the two species are distinct, 

 the character on which he relies principally is the somewhat greater dis- 

 tance betwen the anterior margin of the posterior coxa and the posterior 

 border of the middle coxal cavity in fraternus than prevails in semisul- 

 catus. I have not been satisfied with my study of this character. 



GRAPHODERES 



In this genus Dr. Sharp has discovered a variability in the number of 

 the small palettes on the anterior and middle tarsi of the male. 



In view of the very great resemblance between the so-called species, it 

 is difficult to imagine that the variability indicates specific distinction. I 

 have examined a number of males and very few agree among themselves. 

 From an examination of the species in the cabinet of Dr. Sharp, I be- 

 lieve that the separation of fasciatocollis Harr., perplexus Slip., and 

 elatus Shp., from cinereus entirely unwarranted by the evidence afforded 

 by other species of recognized variability in tarsal vestiture. 



On the other hand I have seen three males, two collected by myself in 

 Northern California and a third in Washington Territory, in which the 

 middle tarsi of the male are not at all dilated, nor are there any palettes. 



