ON CREEPERS. 105 



ers resemble in shape and construction, and also in sizes 

 and colors, the bodies, legs, etc., of their parent flies. 

 Their creeper skins are thicker than those of the drakes 

 and duns, and most of them beautifully marked and 

 lined with dark brown on the top of the head, shoul- 

 ders, and down the back. They are very active, and 

 run as quick in the water as the flies do upon land, un- 

 til the time when they produce their flies ; they then 

 repair to the shallows and edges of the streams, 

 to fix to some substance preparatory to their hatching. 

 Some leave the water and run up the stems of plants 

 that grow by its side, and fix to the under-sides of leaves, 

 but, according to observation, by far the greatest num- 

 ber fasten themselves by the belly and under-parts with 

 some glewy matter, peculiar to them, to the under-sides 

 of stones that lay just without the edges of the water, 

 which enables the flies to split open their creeper skins 

 at the shoulders, and unsheathe their legs, whisks, and 

 feelers. Numbers of the empty creeper skins may be 

 seen on the under-sides of stones taken up by the hand 

 just without the edges of the water, and often the new 

 hatched flies beside them. 



IST. STONE FLY CREEPER. Length, about seven- 

 eighths ; head, shoulders, body, legs, whisks, and 

 feelers, resembling those of the flies, but more bulky, 

 and the legs are fringed ; ground color of the upper- 

 parts, brown, of lighter or darker shade, distinctly 

 lined and marked with dark brown ; belly and under- 

 parts, shades of yellow. At the time of hatching they 

 repair to the edges of the water and fasten themselves 

 to the under-sides of stones, where they hatch their flies, 



