275 



HABITS OF I.ARVAE 



The larvae of all species are aquatic, living in swift-running 

 streams, and particularly in those that have rocky bottoms — to which 

 they attach themselves by means of the suckers on the ventral surface 

 of their bodies. 



The food consists of diatoms, algae, and other small aquatic or- 

 ganisms. 



HABITS OF IMAGINES 



The imagines are never found except in the vicinity of streams 

 suitable for their larvae. The females are predaceous, feeding upon 

 small insects such as chironomid midges; the males are recorded as 

 feeding on nectar. 



Owing to the fact that the larvae require very rapidly flowing pure 

 w^ater as their habitat no species are likely to be found except in moun- 

 tainous regions, and it is improbable that any occur in Illinois. 



BiBIOCFPHALA sp. ? 



Larva (PI. XL, Fig. i).— Length, 9-10 mm. Pale brown on dor- 

 sum, yellowish white on venter; head and chitinized dorsal thorns 

 black. 



Antennae elongate, constricted portions of joints whitish, the re- 

 mainder black ; entire dorsum of head chitinized, black ; mouth-parts 

 pale. Thoracic segments without thorns ; a black triangular chitinized 

 area on dorsum proximad of the first abdominal armature. Last 

 segment of complex and all the abdominal segments except the apical 

 wath 4 stout horn-like protuberances on middle of dorsum, a much 

 longer one near each lateral margin, and a pair of them on lateral 

 margin, the upper one, with a shoulder at its middle, directed outward 

 and armed at apex wath 2 long hairs, the lower one directed slightly 

 downward; apical segment with a pair of protuberances on dorsum 

 and a number of long hairs on margin of apex of venter. Ventral 

 suckers of moderate size. Lateral ventral blood-gills 5 in number in 

 each group ; apical blood-gills stout, 4 in number. 



Pupa (PI. XL, Figs. 2, 4). — Length, 6.5-8 mm. Dark brown. 



Thoracic respiratory organs consisting of the usual 4 upright 

 plates (Fig. 6), the length of the outer one being about 1^4 times as 

 great as its greatest width. Dorsal surface covered with minute, slight- 

 iv raised dots ; each abdominal segment with a group of larger black- 

 ish dots on each side about midway from median line to lateral 

 margin, and between this group and the lateral margin a slight cleva- 



