Male Tarsus in Adephagous Coleoptera. 327 



been developed at the expense of complete suppression of all 

 the glandular hairs in their neighborhood. 



Studied from specimens sent from Switzerland, by Mr. 

 Fritz Rlihl. 



DYTISCUS. 



Anterior tarsi of male with three basal joints dilated and 

 forming a large nearly circular patella, having two large 

 palettes and numerous small ones on the first joint, and small 

 palettes only on the second and third. Middle tarsi with the 

 three basal joints dilated and clothed beneath with glandular 

 or spongy pubescence. This is a large genus, and, with a 

 pattern which is on the whole ver}- constant, shows many 

 minor variations. Of the five species I have been able to 

 study, four are figured. 



D. MARGiNALis Linn. Plate VII, Fig, 6. 



Two large palettes on basal joint and about forty-three 

 small ones, the latter arranged in five tolerably regular trans- 

 verse rows of which the marginal one contains eighteen 

 palettes. Second joint with two complete transverse rows of 

 small palettes and a few intercalated — one at one end, five at 

 the other — forty-three in all. Third joint with confused rows 

 of small palettes, about sixty-eight in number. 



Studied from European specimens. Resembles very closely 

 the foot of D.fascixentris Say. A large palette of this species 

 is shown on Plate VIII., Fig. 11. 



D. FAscivENTRis Say. Plate V, Fig. i. 



Very closely resembling the preceding species, the patella 

 however being a little more elongate, the basal joint compara- 

 tively narrower and longer. The marginal row on the basal 

 joint consists of only fourteen palettes and there are but eleven 

 others on the joint besides the two large ones. The second 

 joint bears an anterior and posterior marginal row of respect- 

 ively twelve and fifteen palettes with a single marginal one 

 intercalated. Third joint with forty-two small disks arranged 

 in somewhat regular transverse rows. 



