414 H. E. EWING. 



organ and pectinate. Pseudostigmata funnel-shaped ; pseudostigmatic 

 organs clavate and slightly recurved. 



Abdomen about two-thirds as broad as long ; pteromorphae triangular 

 and not extending beyond the base of the cephalothorax ; they are 

 about one-third as long as the abdomen. Dorsum of abdomen bear- 

 ing about a dozen stout, slightly curved, pectinate bristles. Genital 

 covers twice as long as broad and situated about one and one-half 

 times their length in front of the anal covers. 



Legs short ; anterior pair about three-fifths as long as the abdomen. 

 Tarsus and tibia subequal. Unguis tridactyle. 



Length, 0.56 mm. ; breadth, 0.42 mm. 



Under old pieces of wood. Collected by the writer at 

 Areola, Illinois. A few specimens. 



Gen. ORIBATELLA Banks. 

 No large, spatulate hairs on the dorsum of the abdomen ; 

 tarsus of leg one tapering at the distal end, not broadened. 

 Lamellse large and attached to the dorsal surface of the 

 cephalothorax by their posterior margins only. 

 One species. 



Oribatella magiiilamellata n. sp. 

 (Plate XV., Figs. 21, 22.) 



Dark chestnut brown ; integument thick, surface smooth. 



Cephalothorax rather small, triangular and almost entirely hidden 

 by the broad, long lamellae ; lamellae very large, extending the entire 

 length of the cephalothorax and projecting slightly beyond the tip of 

 the rostrum, one-third as broad as long, notched in front. From 

 the lateral corner of the lamella extends a sharp curved cusp ; from 

 the median corner extends a very stout, slightly pectinate bristle curv- 

 ing slightly towards the median plane, and as long as the lamella is 

 broad. One pair of tectopedia present which are one-half as long as 

 the lamella. Interlamellar hairs long, curved, slightly pectinate, as long 

 as the lamella? themselves and situated at the base of the lamellae ; 

 anterior lateral hairs about two-thirds as long as interlamellar hairs, 

 strongly curved and pectinate. Pseudostigmatic organ somewat longer 

 than femur one, strongly clavate, directed forwards and towards the 

 median plane. 



Abdomen two-thirds as broad as long ; pteromorphae about one-half 

 as long as abdomen, truncate in front and not projecting beyond the 

 anterior margin of abdomen. Anterior free margin of pteromorphae 

 convex. Genital covers subrectangular, of equal breadth throughout, 

 somewhat smaller than the anal covers, and situated twice their length 

 in front of the latter. Anal covers subtriangular in shape, much broader 



