Sept., 1909.1 EwiNG : New American Oribatoidea. 119 



Div. I. 



1. No true lamella present ; a pair of lateral lanier.x% very closely appressed to the 



dorso-vertex. (Subdiv. [a).) ^• 



Lamella blade-like. (Subdiv. {/>).) O. qiiadricuspiJata s^. nov. 



2. With dorsal surface of cephalothorax sloping very markedly downward as you pass 



from the dorso-vertex to rostrum ; black species O. 7iigra sp. nov. 



Dorsal surface of cephalothorax not receding as you pass from the dorso-vertex to 

 rostrum ; color brown 3- 



3. Wings of abdomen large, two thirds as broad as the cephalothorax when viewed 



from above ^- >nacroptera. sp. nov 



Wings of abdomen about one third as broad as the cephalothorax wheh viewed 

 from above '*' 



4. Wings of abdomen with wrinkles 0. rngosala sp. nov. 



Wings of abdomen smooth O. mimtta s^. nov. 



Oribata quadricuspidata, new species. (Plate II, Figs. 4 and 5.) 

 Light brown ; integument rather thin and brittle, surface smooth. 

 Cephalothorax about one third as long as the abdomen and very peculiar in pos- 

 sessing grooves for the reception of the lamellae, which gives the dorso-vertex the 

 appearance. of projecting over the base of the lamellae. Lamellae prominent, almost 

 as long as the cephalothorax and very deeply bifid in front, the inner cusps of the 

 lamellK extend about one half their length beyond the tip of the outer cusps. No 

 translamella. Two pairs of lateral lamellae, the inner pair is much the longest and 

 is curved towards the median plane ; the outer pair is short and stout. Lamellar 

 hairs long, slightly curved at the base ; interlamellar hairs similar to lamellar hairs, 

 but straight and longer ; they are situated almost approximate to the posterior margm 

 of cephalothorax ; anterior lateral hairs stout, curved and pectinate. Pseudostig- 

 matic organs very large, clavate and directed forwards and towards the median plane. 

 Palpi prominent. 



Abdomen subglobose ; pteromorphae triangular, truncate, not extending beyond 

 the anterior margin of abdomen. Genital covers slightly smaller than anal covers 

 and situated one and one half times their length in front of the latter. Abdomen 



hairless. 



Legs rather small and bearing several stout, short, pectinate bristles. Ungues 



tridactyle. 



Length, 0.32 mm.; breadth, 0.21 mm. 



Under the bark of shell-bark hickory. Collected by J. D. Hood, 

 at Urbana, Illinois. Two specimens. 



Oribata nigra, new species. (Plate II, Fig. 6.) 



Body black; legs and pteromorphie brown. Integument thick and smooth. 



The cephalothorax is peculiar in that the dorsal surface slopes downwards 

 rapidly from the posterior part of the cephalothorax to the rostrum, the rostrum being 

 much lower than the posterior dorsal surface of the cephalothorax. Lamellae rudi- 

 mentary ; translamella absent. Superior hairs situated laterally, long and curved 



