Insect Study 



389 



Caddis-worm case fastened to leaf 

 for pupation period. 

 Photo by J. T. Lloyd. 



get the caddis-worm, if they knew 

 where it went. Sometimes caddis- 

 worm cases have been found in the 

 stomachs of fishes; perhaps they 

 serve as fish breakfast-food. 



While it is difficult to see the 

 exact operation of building the 

 caddis-worm house, the general 

 proceeding may be readily observed. 

 Take a vigorous half-grown larva, 

 tear off part of the sticks and bits of 

 leaves that make the log cabin, and 

 then place the little builder in a tumbler with half an inch of water at the 

 bottom, in which are many bright flower petals cut into strips, fit for 

 caddis lumber. In a few hours the little house will look like a blossom 

 with several rows of bright petals set around its doorway. 



When the caddis-worm gets ready to pupate, it fastens its case to some 



object in the water and then closes 

 its front and back doors. Different 

 species accomplish this in different 

 ways; some spin and fasten a 

 silken covering over the doors; 

 often this is in the form of a pretty 

 grating; others simply fasten the 

 material of which the case is made 

 across the door. But though the 

 door be shut, it is so arranged as to 

 allow the water to flow through and 

 to bring oxygen to the thread-like 

 gills, which are on the pupae as well 

 as on the larvae. When ready to 

 emerge, the pupa crawls out of its 

 and climbs to some object 



case 



Grating of silk over the door of a caddis- 

 worm case to protect the pupa. 

 Photomicrograph by J. T. Lloyd. 



above the water, sheds its pupa skin, and the adult insect flies off. 

 In some species, living in swift water, the adult issues directly from the 

 water, its wings expanding as soon as touched by the air. 



Caddis-flies are familiar to us all even if we do not know them by name. 

 They are night fliers and flame worshippers. Their parchment-like or 

 leathery wings are folded like a roof over the back, and from the side 

 the caddis-fly appears as an elongated triangle with unequal sides. The 

 front wings are long and the hind ones shorter and wider ; the antennae 

 are long and threadlike and always waving about for impressions; the 

 eyes are round and beadlike ; the tarsi, or feet, are long and these insects 

 have an awkward way of walking on the entire tarsus which gives them 

 an appearance of kneeling. Most of the species are dull-colored, brown- 

 ish or gray, the entire insect often being of one color. Caddis-flies would 

 not be so fond of burn- 

 ing themselves in lamps 

 if they had the human 

 sense of smell, for the 

 stench they make when Caddis-fly. 



nauseat- Photo by J - T - Lloyd - 



scorching 



is 



