194 



NATURE STUDY REVIEW [8 :5— May, 1912 



long-legged, two-winged insects which fly about in damp shady 

 places and which look like huge mosquitoes. The larvae feed on 

 decaying vegetation and they can be kept in an aquarium which 

 contains wet moss, slime, or damp decaying leaves. 



Caddice Fly Larvae (Fig. 23). 



Sweepings of the dip net in any kind of aquatic situation is 

 pretty sure to bring up some curious bits of wood or stone which 

 may at first escape the eye of the young collector and be cast 

 aside with the rubbish. Possibly they may be first discovered on 

 the bottom of some clear pool in which the youth will be startled 

 to see some little masses of stories and sticks which look like the 

 other objects on the bottom but which move. These are the cases 

 or houses of the caddice fly larvae (sometimes called caddice 

 Vv^orms) and a little further search about the collecting grounds 

 will reveal a surprising variety in the way in which these cases 

 are built. Some are made of small pebbles and sand ; some are 

 made of little sticks crossed up in such a way as to make a tiny 

 log cabin affair ; some are made of sticks placed lengthwise ; some 

 are made of bits of leaves and grass, and so on. Although very 

 rough on the outside, the cavity on the inside is lined with smooth 

 silk. The dark headed larva lives in this cavity and carries the 

 case about with it as it moves from place to place, by thrusting 

 the head and legs out through the opening of the case. There 

 are a pair of hooks on the end of the abdomen which help to hold 



the case in place. These creatures 

 feed on aquatic plants. After a 

 certain period of growth the 

 larva fastens the case to some ob- 

 ject, closes the opening at each 

 end of the case and changes into 

 a pupa. The pupa finally leaves 

 the case, climbs up out of the 

 water on some stem or other ob- 

 ject, and there hatches into an 

 adult which is a brown or gray- 

 ish, moth-like insect with long 

 thread-like antennae and long 

 rather narrow wings which have 

 Immature Insects: 24, Crane very fine hairs scattered over 

 Fly Larva ; 25, Caddice Fly the surface. These adults can be 

 Larva ; 20, Blood Worm collected around lights at night. 

 (Ciin«)N()M0us Larva). Those larvae which live in 



25 



