Male Tarsus in Adephagous Coleoptera. 329 



well the structure of these parts in all the species of Dytiscus 

 which I have studied, the chief difference lying in the density 

 of the vestiture. There seems to be no direct correlation 

 between the number of palettes on the anterior feet as com- 

 pared with the intermediate. 



COLYMBETES. 



Composed of species with very heterogeneous male charac- 

 ters — anterior tarsi either dilated or compressed, with or 

 without palettes and glandular pubescence. 



CoLYMBETEs scuLPTiLis Harris. Plate VIII, Fig. 10. 



Anterior tarsus dilated, not compressed, basal joint with 

 twelve palettes in two rows of six each, those in the marginal 

 one with longer stalk than the others; a median irregularly 

 Y-shaped patch of pubescence. Second joint with a single 

 submarginal row of six; third joint with one of four palettes 

 all alike. 



No true palettes are visible on the tips of the sexual hairs 

 in my specimens, but I suspect they may have been acci- 

 dentally removed, either in preparation of the slide or before 

 the insect came into my hands. 



Studied from specimens from Michigan. This foot recalls 

 that of Cyhister in the arrangement of the rows of palettes as 

 well as in the possession of the patch of pubescence on the 

 heel. 



