MOTHS 81 



frenulum at the base of each hind- wing, which hooks 

 under a kind of strap (the rttinaculum) on the under- 

 side of the fore-wing. In the male the frenulum is 

 usually a single curved bristle, but in the female it 

 commonly consists of three stiff hairs. This inter- 

 locking arrangement is not universal, however, for in 

 some moths, and in all butterflies, the co-ordination of 

 the two wings of the same side depends solely upon 

 the underlapping of the fore-wing by the anterior part 

 of the hind-wing. 



The larvae of Lepidopterous insects are always 

 caterpillars, usually with five pairs of prolegs, though 

 there are many remarkable exceptions to this rule. 

 They generally feed on vegetable matter, but a few 

 kinds (e.g., those of the " clothes-moths ") eat sub- 

 stances of animal origin, such as wool or feathers. 

 Among the lowliest of all moths the pupa is free, and, 

 like that of the caddis-fly, equipped with functional 

 mandibles ; but as we pass from the lower to the 

 higher families, we find that the pupa becomes more 

 and more obtected i.e., covered by a general harden- 

 ing and thickening of the outer skin, and consequently 

 less and less capable of movement. The pupal stage 

 is usually passed in concealment, either in a subter- 

 ranean cell, or in a cocoon ; but, with the exception 

 of some " skippers," butterflies do not spin cocoons. 



What is the difference between a moth and a 

 butterfly ? From the scientific standpoint no satis- 

 factory distinction can be made. It has already been 

 said that butterflies have no frenulum, but the same 

 is true of certain moths ; while most of the other tests 

 that have been suggested such as the manner of 

 holding the wings in repose, or whether the insect 

 flies at night or by day are by no means infallible. 

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