286 A NATURALIST IN THE GREAT LAKES REGION 



headed (Fig. 442), banded, and Johnny darter are all able by 

 their large pectoral and anal fins to hold themselves among the 

 stones in the swift current and search under them with their 

 pointed heads for insect larvae. The sucker-mouthed minnow 



Fig. 439. — Sucker-mouthed minnow, Phenacohius mirahiUs 



has similar feeding habits. The stone roller, as the name 

 indicates, moves the smaller stones in his efforts to nibble off 



the slime, while the hammer- 

 head sucker can dislodge 

 quite good-sized stones in 

 his effort to locate hiding 

 Fig. 440.— Fan-taUed darter, £/Aeo5/owia animals. On the other 

 flahellare, two-thirds natural size. ^^^^^ ^^^^^ ^^^ ^^^^^.^ ^^^ 



found in the sluggish waters over mud bottom. Such are the 

 black bullhead, hog sucker, and golden shiner. 



Fig. 441. — Black-sided darter, Hadroptenis aspro * 



No association contains more remarkably adapted animals 

 than this lotic or Hydropsyche association. The net building 

 caddis fly (Hydropsyche) (Fig. 443) forms a cornucopia-shaped 

 tube open at both ends with the large flaring end upstream, 



