L 



SIMULIUM. 65 



indistinguishable, hind tarsus formed as in female; claws trifid. 

 Wings normal. 



Length, 2-2.5 mm. 



Type. — Locality, Illinois River, at Havana. A very large number 

 of both sexes were taken, many of them reared from pupae which 

 were found in the river. A description of the pupa follows. 



Pupa. — Yellow, becoming brown before emergence of the imago, 

 the colors of which may be distinctly traced through the body wall 

 of the pupa some time before it is ready to emerge. The respiratory 

 organs branch near the base, generally into three main stems, the 

 branch or stem w-hich is directed anteriorly again breaking into two 

 stems which are bifid from near their bases ; the central stem is again 

 subdivided into three smaller branches, the central one ending in 

 2 filaments and the other two in 4 each; the posteriorly directed 

 branch generally divides at near to the base, a further subdivision 

 taking place a little farther up, each of the latter branches generally 

 having 2 filaments, making as a rule from 22 to 24 or 25 filaments in 

 all. The abdomen has on the fourth and fifth segments (counting 

 the segment show^ing just behind the scutellum as the first) a trans- 

 verse row of four short hooks, the points of which are turned ceph- 

 alad ; on each side of the dorsal line, a somewhat similar series on the 

 eighth segment which are more numerous, smaller, and almost con- 

 nected in center ; on the ninth segment the row is almost continuous 

 on the posterior margin of the segment. The fifth, sixth, seventh, 

 and eighth ventral segments have each two hooks on each side which 

 are much closer, in each pair, to each other than the transverse space 

 between the pairs. 



Length, 3-3.5 mm. 



The cocoon, which is generally attached to stems of plants or to 

 posts in the stream, is very similar to that of johannseni. 



The type and paratypes of this species are in the Illinois State Lab- 

 oratory of Natural History. 



I have much pleasure in dedicating this species to Dr. Stephen A. 

 Forbes, who has done so much to elucidate questions in connection 

 with this group on the Illinois River. 



Simulium johannseni Hart. 



This species is very clearly described by Hart in the Twenty- 

 seventh Report of the State Entomologist of Illinois, 1912, page 32. 

 It is only necessary for me to point out that the male has the three 

 vutta? on the scutum generally distinct and the pilosity whitish. The 

 color of the legs in both species is as given in the description here- 

 with for forhesl., although in alcoholic specimens the color is as fig- 

 ured by Hart in his original description. Fresh females of johannseni 



1012.5°— 14 Ti 



