Male Tarsus in Adephagous Coleoptera. 325 



also considerably larger, extending much farther forward on 

 the joint. Algeria. 



It is perhaps worthy of note that there appears, with the 

 scanty material at hand, to be a direct correlation between the 

 size of the dilated tarsi and the number of palettes; thus in 

 C explanatus which has the smallest foot of the three species, 

 I find only seventy-four palettes: in C. jimhriolatus with a 

 somewhat larger foot there are seventy-six, while on the still 

 larger one of C. tri'punctatus there are eighty-six. The ar- 

 rangement by series is given below. 



1234 Total 



There may be a variation within specific Hraits as well as 

 that which I have noted above, but material is not now at 

 hand for the discussion of the question. 



THERMONECTES. 



Anterior tarsi of male dilated, the first three joints forming 

 a nearly circular plate, furnished beneath with several palettes, 

 the three basal often larger. Intermediate tarsi simple. 



Thermonectes ornaticollis var. mgrofasciatus Aube. 

 Plate VIII, Fig. 7. 



Patella equal in length and breadth, the basal joint longer 

 than both the others. The palettes are arranged as follows: 

 Three large ones forming a triangle, and six smaller, marginal 

 on the basal joint; seven on the second and six on the third 

 joint, arranged along the anterior and side margins and of 

 about the same size as the smaller palettes on the basal joint. 

 Fringing hairs, few in number, interrupted at the articulation 

 of the tibia and of the fourth joint. 



The palettes resemble those of Dytiscus much more closely 

 than those of Cybister. It exhibits a high type of specializa- 

 tion in the reduction of the number of palettes, while on the 



