LEPIDOPTERA. 69 



wing is distinctly visible. The Lepidoptera have, as a 

 rule, six legs, the normal number of all insects, but in 

 some of the butterflies the fore legs are either wanting 

 or rudimentary. The larvse of the Lepidoptera are 

 popularly termed caterpillars, of various forms and sizes. 

 The body contains thirteen segments, the first of which 

 forms a strong horny head, provided with biting jaws. 

 On the labium there is a slender hollow body, which is 

 in communication with two internal glands, whose 

 function it is to secrete the substance out of which the 

 silky threads are spun. This organ is called the spin- 

 neret, the value of which will be acknowledged when we 

 consider its use in the production of the silk of com- 

 merce. Many of the Lepidoptera, beautiful as they are 

 in their perfect state, are eminently destructive to the 

 gardener and the farmer. Every one is familiar with 

 the nasty green grub that riddles his cabbages and cauli- 

 flowers through and through. The enemies that do 

 this are the larvse of the "Garden White" butterflies, 

 which, like the larvse of most of the Lepidoptera, are 

 voracious feeders. They grow rapidly, changing their 

 skins frequently. In many species there are two broods 

 every year ; others, again, require two years or more 

 before they assume the perfect state. In the pupa condi- 

 tion the creature is inactive : some enclose themselves in 

 a silky cocoon, others select the lower surfaces of leaves, 

 and roll themselves in, fastening their bodies by silken 

 lines ; others simply bury themselves in the earth, and 

 may often be dug up in the form of dark brown cylin- 

 drical bodies of various sizes. When the insect first 

 emerges its wings are soft and crumpled, as may be seen 

 by all who have kept silk- worm moths. Fortunately 



