Eiving — New North American Acarina. 69 



of the male is the thickest segment; the genual, however, is almost as 

 stout and bears on its inner dorsal aspect an enormous horn of a very 

 characteristic shape and which is fully as long as the segment itself; 

 tibia about one-half as broad as the genual and possessing a prominent 

 quadrate horn on its inner side; tarsus of the usual size. Caruncles of 

 the tarsi of all the legs rather slender. Legs sparsely clothed with 

 hairs. 



Length, 1.10 mm.; breadth, 0.70 mm. 



Under the bark of a rotting maple log. Collected by 

 J. D. Hood at Lyons, 111. 



Uropodidae. 



Body with coriaceous integument, usually much depressed and often 

 possessing impressed fovefe on the ventral surface for the reception of 

 the legs when folded under the body. Mandibles chelate and retractile. 

 First pair of legs inserted within a common body opening with the 

 mouth parts. Nymphs possessing an anal pedicel composed of excreted 

 material for adhering to the integument of insects. Not usually true 

 parasites. 



Uropoda Latreille. 



Ventral surface of the body showang deep sculptures for the reception 

 of the legs; body outline oval, not broken; dorsum sometimes pitted but 

 never sculptured; leg I possessing claws. 



Five species. 



KEY TO SPECIES. 



1. Integument of body deeply and uniformly pitted, pits large 



V. cribraria. 



Integument of body smooth 2. 



2. Body uniformly rounded behind 3. 

 Body pointed behind U. folsomi. 



3. Antero-lateral margin of body convex U. illinoiensis. 

 Antero-lateral margin of body concave 4. 



4. Body almost as broad as long U. fusca. 

 Body about two-thirds as broad as long XJ. pallida. 



Uropodii Cfibraria n. sp. 



PL X. f. 29. 



Brown; integument very coarsely pitted, giving the whole body a 

 sieve-like appearance. 



Body oblong, uniformly rounded behind and somewhat pointed in 

 front, with a row of stout curved bristles around the margin. Female 

 genital plate much more finely pitted than the rest of the body, about 

 three-fifths as broad as long and extending from behind the coxa? of 

 the last pair of legs to between the second pair of legs. Male genital 

 opening on the median line half way between the third and fourth 

 pair of legs. 



Anterior pair of legs scarcely one-half as long as the body; tarsus 

 of leg I almost as long as the three middle segments and well clothed 



