112 INSECUTOR INSCITI^ MENSTRUUS 



very close to curriei, differing principally in being slightly 

 larger. There may be a few specimens among my 768 curriei, 

 but I have not detected them and more probably campestris 

 inhabits a different area from that traversed by me, 



The two specimens differ in the male genitalia. Not as 

 radically as given in the monograph, which should be cor- 

 rected on this point, but sufficiently. In curriei, the basal lobe 

 of the sidepiece has two spines, a large curved one centrally 

 and a shorter straight one at the margin. In campestris the 

 middle spine is straight and about as stout as the outer one in 

 curriei, while the outer one is absent, being represented by 

 two stout setae. This is an unexpected divergence, since the 

 two spines are present and of the same structure in curriei, 

 quaylei, onondagensis, and even the European dorsalis Meigen, 

 though somewhat approximate in the latter. In campestris, 

 however, the type is altered. 



Aedes canadensis Theobald. i 



Not found in the plains and in the river valleys only near the 

 mountains. The species is characteristic of the northern At- 

 lantic coast region, extending even to Florida. It ranges 

 westward through Canada to the Rocky Mountains. The 

 species is not recorded by Parker. 



Aedes nigromaculis Ludlow. 



This species is characteristic of the prairie section of the 

 river valleys. It never comes into the timbered country. I 

 did not encounter it west of the Great Divide. 



The males form a loose active swarm above prominent 

 objects on the prairie. On the evening of July 15, at Laurel, 

 they gathered above the writer's head, rising to a great height 

 when disturbed, gradually settling to two or three feet above 

 the head. After half an hour the swarm became partly con- 

 fused with a swarm of curriei, which gathered in a similar 

 position, but lower. Another visit to the Sarcobatus bush men- 

 tioned above, after sunset, showed three swarms of males, 

 nigromaculis above the bush high up, idahoensis above but 

 lower, and curriei low and a little to one side. 



