138 THE CANADIAN ENTOMOLOGIST. 



The claws of the anterior tarsi $ are very nearly equal, the last joint 

 about one and a half times the length of the four preceding joints and 

 not broader than these, as is the case in the next two species. The 

 tooth of the tarsal claws is much longer than in either of the foregoing 

 species. This species is readily recognized It is less widely distributed 

 than the others, but specimens are known to me from Pennsylvania, Mis- 

 souri and Georgia. 



J/, triangularis Say. More elongate and narrower than either the 

 preceding or next species. Prosternal groove closed in front. Ventral 

 segments smooth and shining, except for a narrow space on each side, 

 each segment with a conspicuous pale spot. 



The male has the claws of the anterior tarsi very unequal, the anterior 

 or outer being much larger and stronger, the last tarsal joint oblong, wider 

 and a little longer than the preceding joints together, and much longer 

 than wide. 



This species occurs from the Middle States to Oregon, southward into 

 Mexico. 



H. insularis Cast. Larger than the preceding species and less slender. 

 Prosternal groove closed. Abdomen smooth, the sides narrowly opaque, 

 the yellow spots very indistinct or absent. 



The male has the anterior claws very unequal, the last joint of the 

 front tarsi as long as the preceding four, broadly triangularly dilated, 

 slightly broader than long. 



When once the form of these two species is fixed in the eye, there is 

 no difficulty in distinguishing them independently of the male characters, 

 which are very obvious. 



This species is known to me from Texas and Arizona. It extends to 

 Guatemala, and occurs also in the Antilles. 



Tropistcrnus apicipalpis Chevr. This species should be added to 

 our lists. It is much larger than our other species and more narrowed 

 posteriorly. The terminal joint of the maxillary palpi is a little shorter 

 than the preceding, thereby approaching Hydrophilus. The last ventral 

 segment has a strong spiniform crest. It is more nearly related in our 

 fauna to glaber and mixUis, and differs from both not only in its larger 

 size and by being more narrowed posteriorly, but also by the middle and 

 hind femora being very dissimilarly punctate. 



Occurs in Arizona, the peninsula of California, and in Mexico. 



