CHAPTER III 



CADDIS-FLIES 



The caddis-flies, which are called Trichoptera by 

 modern entomologists, comprise a number of aquatic 

 insects of which the larvae make either movable cases 

 which they drag about, or fixed ones that they anchor 

 to heavy stones, going in and out of them according 

 to their inclination. The caddis, sometimes most 

 incorrectly called caddis-worms, are plentiful in the 

 majority of rivers in Great Britain and abroad. 

 Every observant fisherman has seen those with 

 movable cases literally in hundreds on the bed of the 

 stream or of a carrier, and until he had examined them 

 has wondered how the solid-looking structure of stone 

 or of twigs and other vegetable matter could move 

 about. When a specimen has once been taken in the 

 hand, the sight of the head, thorax, and legs protrud- 

 ing in front and crawling along towing the case behind 

 has elucidated this mystery. 



The caddis-flies undergo complete metamorphosis, 



and the various stages of their 



Life history of caddis- existence after emerging from 



flies. the eggr therefore are larva, 



pupa, and imago. The eggs 

 of some are carried in ovoid masses on the ventral 



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