CHAPTER VII 

 CADDIS-FLIES, MOTHS, AND BUTTERFLIES 



caddis-flies were formerly included with the 

 JL Neuroptera, but they are now treated as a 

 distinct order (the fourteenth on our list viz., 

 Trichoptera). They are not only moth-like in appear- 

 ance, but many details of their structure indicate 

 actual relationship with the less specialized Lepi- 

 doptera, or " scale-winged " insects. For example, 

 they agree with the members of the two lowest 

 families of moths in having on the hind margin of the 

 fore-wings, near its base, a little process (called the 

 jugum) which apparently serves during flight to co- 

 ordinate the action of the two wings of the same side. 

 Caddis-flies have long, slender antennae, with many 

 joints. When at rest, the fore-wings arc brought 

 together like a roof above the hind-wings, which fold 

 up fan-wise. The mandibles of the adults are either 

 absent or very rudimentary, while the two pairs of 

 maxillae unite with the labrum to form an imperfect 

 sucking apparatus. The larvae, however, have biting 

 mouth-parts, and feed on vegetable matter. They live 

 in ponds and streams, and are the well-known 

 " caddis-worms/' which build protective cases of 

 small stones, shells, pieces of stick, etc., fixed together 

 with silk spun from the mouth. Their thoracic legs 

 are well developed, while there are two strong hooks 



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