OF WASHINGTON, VOLUME XI, 1909 141 



Cymberemaeus parvula, new species. 



Yellowish brown. Cephalothorax blunt in front, punctulate above 

 and reticulated; pseudostigmatic organ of moderate length, clavate ; 

 abdomen elongate, flat ; a central area separated by a distinct groove 

 from the margin, the central area reticulate, the margin mostly striate, 

 partly reticulate ; between the cephalothorax and abdomen there is on 

 < arli side a prominent projection; on apical margin are four tiny 

 clavate hairs. Venter and sternum strongly granulate ; anal and ventral 

 apertures about one-third their length apart. Legs short and thick, 

 with few very short, simple hairs; on leg I the penultimate joint has a 

 long apical process extending over the tarsus ; one claw. 



Length, 0.35 mm. 



From Guelph, Ontario, Canada, under bark of iron wood, 



March 6. 



Family TYROGLYPHIDyE. 

 Histiostoma valida, new species. 



In general characters and appearance this species is like H. gracilipes, 

 described and figured in my Revision of the Tyroglyphidae, but differs 

 in that the third joint (from the tip) in all legs is twice as long as the 

 penultimate joint, and nearly twice as long as the preceding joint. 

 The tarsi are even more slender than in H. gracilipes; the tips of the 

 palpi are also longer than in that species ; and I cannot see any hairs on 

 the abdomen. 



Length, 0.3 mm. 



From Gnelph, Ontario, Canada; on horse-manure. 



Family AXALGESIDyE. 

 Pterodectes armatus, new species.^ 



Similar to Pt. cylindricus. Dorsum- with two shields ; the anterior 

 narrowed in front and indented on the sides, its hind margin distinctly 

 undulate, and with a pair of bristles above ; apex of female as in Pt. 

 cylindricus, but each lobe has two bristles instead of one. In the male 

 the tip of abdomen is more deeply incised, the lobes broader at tip, and 

 three bristles inward of the large one ; from the tip of dorsum there 

 extends back beyond the lobes a rounded, hyaline plate. 



Length, 0.5 mm. 



Guelph, Ontario, Canada, on various birds; song sparrow, 

 hermit thrush, junco, robin, white-throated sparrow, cedar 

 bird, palm warbler, black and white warbler. 



Pterodectes muticus, new species. 



Similar to Pt. rutilits, but with rather shorter legs; a pair of shorter 

 bristles on cephalothorax. In male the tip of body more deeply in- 



