How Animals Work. 



In collecting the water weeds to which Melicerta at- 

 taches its tube, we are very likely to gather some of 

 those strange aquatic insects called Caddis-worms, which 

 delight to clothe their soft and otherwise unprotected 

 bodies in garments composed of all sorts of odds and 

 ends of plant and animal remains (6, Plate VI.). They 

 vary a great deal in their choice of materials and per- 

 fection of workmanship, some appearing to be singu- 

 larly slovenly and untidy, weaving together a perfect 

 jumble of bits of dead leaves and twigs of all shapes 

 and sizes into a rough more or less tubular garment. 

 There is method in their madness, however, for prob- 

 ably their untidy clothes, when the insect suddenly 

 withdraws within them and remains quiescent, look 

 far more like part of the natural debris of the bottom 

 of the pond than do the more tidy and symmetrical 

 productions of some of their relations. A very large 

 proportion of the Caddis larvae collect pieces of leaves 

 or the small stems of water plants, which they fasten 

 together with a natural silky secretion, sometimes lining 

 the whole tube or case with silk ; but there are several 

 who form their tubes out of grains of sand, particles 

 of earth, and small stones, and one is particularly fond 

 of collecting the tiniest of water-snail shells, which it^ 

 attaches on to its case with a blissful disregard as to 

 whether the shell is still tenanted or not, so that a poor 

 baby water snail may often be seen, upside down, an 

 unwilling captive on top of the tubular case of this 

 Caddis larva. It appears at first perhaps a strange 

 habit, this collecting together of materials so diverse, 

 and their formation into a tubular portable dwelling 

 or garment. But we must remember that although 



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