Larvae and their Work 



seen the decoys used for the capture of wild-duck in the 

 fen country, or at any rate pictures of them. These traps 

 consist of nets arranged to form a long tube, spread wide 

 at the mouth and gradually tapering off into quite a narrow 

 tunnel. The ducks are lured into the large open end and 

 driven up into the narrow part, where they are caught. 



Whether man reaped his idea for this novel form of trap 

 from the caddis-flies we cannot say, but it is a fact that 

 one kind of caddis larva builds a home which is an exact 

 replica in miniature of a fenland duck decoy. The open 

 end of this funnel-shaped dwelling is composed of strong 

 silk netting, held in position by a few arched twigs ; in 

 the narrow end of the funnel the larva lurks. The mouth 

 of the dwelling always faces up-stream, in order that 

 water insects may be carried down into it ; there they are 

 seized and devoured by the larva. 



No one watching some free flying moth disporting itself 

 on the evening air would ever suspect that the larvae of 

 some of these children of the night live in water and, what 

 is more, construct larval cases rivalling those of the caddis- 

 flies. One of these insects, the brown china-marks moth, 

 deposits its eggs on the under sides of water-lily leaves and 

 covers them with a jelly-like covering. By the way, this 

 habit of many water-dwelling animals of covering their 

 eggs with jelly is not without its uses : the jelly protects 

 the eggs from injury by hungry fishes. The first act- of the 

 caterpillars, when they hatch from the eggs, is to build a 

 home for themselves. This they do by cutting two neat little 

 oval-shaped pieces from the leaf surface and binding their 

 edges together with silk, so as to form a lens-shaped shelter. 

 The small china-marks moth lays its eggs on duckweed, 

 a well-known floating water plant. The larva spins 

 together a number of the round duckweed leaves with silk 

 and builds a tubular case, remarkably like the cases of 

 some caddis-fly larvae. 



A very curious little creature is a leaf-eating beetle of 

 aquatic habits. The female eats circular holes in the 



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