BROOK INSECTS 



63 



and October (near Stanford University) and winged adults of 



which were issuing constantly thru those months. The young 



May-flies live for many months, some species for one or two or 



even three years, in the water. 



The life of the adult is, on the con- 

 trary, at longest, not more than a 



few days, and some kinds live in 



the winged condition for but a few 



hours. The stone-flies do not spend 



so much time in the water, nor die 



so soon after acquiring wings. 



Caddice-worms — Firmly attached 



to stones, especially large ones, in 



swift parts o± the stream, may be 



found small cases (fig. 36 b) or 



houses composed of many small 



pebbles fastened together with silk. 



In more quiet places in the stream 



may be found either attached to 



stones or resting on the bottom, or 



sometimes floating in the water, 



elongate cases (Fig. 37), an inch to two inches long, made of bits 



of wood fastened together with silk or bits of pine needles or even 



grass stems tied cleverly together 

 by silken threads. Or tiny cornu- 

 copias (fig. 36 a) composed of sand 

 grains, may be found. All these 

 are the cases of the caddice-worms 

 or case-woims, and the caddice 

 worm itself may be found snugly 

 concealed in its case. 



Find and collect as many dififerent 

 kinds of caddice-worms cases as you 



Fig, C5, A May-liy. 



Caddice-fly cases made of 



sandta), and pebbles (d). 



