142 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



cised than in Pt. rutilus, and the lobes more divergent, and the largest 

 terminal bristle is longer. In the female the tip of abdomen is divided, 

 but the lobes not divergent, and there is no apical spine, but only an 

 ordinary bristle. 



Length, 0.5 mm. 



Guelph, Ontario. Canada, on vesper sparrow, and phoebe. 



Rivoltasia bispinosa, new species. 



Female Body about one and one-half times as long as broad, broad- 

 est at the shoulders, the abdomen short and broadly rounded at tip. 

 Beak short, depressed ; legs short and stout, tapering from base to 

 tip, leg I about one-half the length of body, leg IV plainly longer than 

 I, each with a few hairs, mostly toward tip, and a long one just before 

 the tip ; on each shoulder is a long bristle and at apex of abdomen are 

 two bristles each side, the outer one two-thirds as long as body, and 

 arising from a small tubercle, the inner one is very short. The male 

 has the abdomen ending in two divaricate lobes, each tipped by a slender 

 curved spine and with another shorter spine pointing inwards from its 

 base ; a long bristle arises from a bulb-like lobe at outside of the apical 

 spine. 



Length, 0.15 mm. 



( aielph, Ontario, Canada, on pigeons. 



Family LISTROPHORID/E. 

 Listrophorus validus, new species. 



Male Pale yellowish hyaline, the lobes of the attaching apparatus 

 brownish. Body a little more than one and a half times as long as 

 broad, broadest just in front of the third legs; the anterior end is dis- 

 tinctly truncate, on each side of head beneath is a large curved thin 

 plate, transversely-ribbed or striate, at the base is a ribbon-like strip, 

 striated the opposite way. Anterior legs are slender, usually, at least, 

 folded over body ; the posterior legs heavier, all tarsi with a long sub- 

 terminal bristle. Tip of abdomen narrow, sightly emarginate, with a 

 bristle at each corner. Dorsum with an anterior shield, reaching back 

 beyond coxae II, back of this shield the abdomen is transversely striate 

 for a short distance, and beyond smooth or much more finely striate ; 

 venter coarsely transversely striate. In the female the body is more 

 slender, three times as long as broad, extending much beyond hind legs, 

 and the anterior legs are more prominent, the femur I being quite long 

 and slender. 



Length, 0.4 mm. 



Guelph, Ontario, Canada, April 26, 1906: taken from musk- 

 rat. 



