352 

 Genus Oribatella Banks. 



Ungues tridactyle; pteromorphae attached to the abdomen 

 only; lamellae large, attached to the cephalothorax by their 

 posterior margins. 



Two species: 



Pteromorphae truncate, not extending beyond the anterior mar- 

 gin of abdomen quadridentata. 



Pteromorphae extending almost to the tip of the rostrum. 

 oval is. 



Oribatella quadridentata Banks. 



1895. Oribatella 4-dentata, Banks, Trans. Amer. Ent. Soc, Vol. XXII., p. 9. 

 189S. Oribata quadridentata, Michael, Das Tier., Lief. 3, p. 19. 



Dark brown; integument brittle; surface slightly rough. 



Cephalothorax about as broad as long and almost entirely 

 hidden from above by the lamellae, which are very large, project- 

 ing beyond the rostrum and ending each in two subequal cusps; 

 lamellae almost touching each other and twice as long as broad. 

 No translamella. Lamellar hairs almost straight, pectinate and 

 directed forward. There are two very much curved, pectinate 

 rostral hairs; also a pair of similar but straight interlamellar 

 hairs; pseudostigmatic organ large, clavate, and pectinate, about 

 two thirds as long as the lamellae. Just behind each pseudo- 

 stigma is a short, stout, pectinate bristle. 



Abdomen almost as broad as long, pteromorphae truncate, 

 not extending beyond the anterior margin of the abdomen, 

 their anterior margin slightly concave. There is a whorl of 

 about a dozen stout, curved, pectinate bristles around the mar- 

 gin of the abdomen. Anal covers slightly larger than the 

 genital covers, and situated about their own length from the 

 posterior margin of the abdomen and twice their length from 

 the genital plates. Legs small and short. 



Length, 0.56 mm.; breadth, 0.38 mm. 



Under logs and boards. Collected by the writer at Urbana, 

 111. Many specimens. Mr. Banks has confirmed the determi- 

 nation of this species. 



