74 BUTTERFLIES 



increases its weight 10,000 times. Even this is not 

 the limit, for some caterpillars live three years ; for 

 instance, the goat moth, which grows to 72,000 

 times its weight on hatching. 



The shapes and colours of caterpillars follow 

 the same laws as those concerning the adult 

 insect, the colour being generally protective be- 

 cause the caterpillar is soft and fleshy and good 

 eating for birds. The colour for this reason is 

 usually green, and those feeding on grass are 

 striped longitudinally, those on larger leaves 

 obliquely, this forming a very effective protection. 

 Others are brown, and so like twigs in shape that 

 even the most experienced may be deceived. Mr. 

 Jenner Weir writes: " After being thirty years 

 an entomologist I was deceived myself. I took 

 out my pruning knife to cut from a plum tree a 

 spur which I thought I had overlooked. This 

 turned out to be a larva of a geometer two inches 

 long. I showed it to several members of my 

 family and defined a space of four inches in which 

 it was to be seen, but none of them could per- 

 ceive that it was a caterpillar." 



Warning colours are well seen in caterpillars. 

 All green and brown ones are readily and greedily 

 eaten by birds, lizards, and frogs, but many are 

 conspicuously coloured and do not attempt to 

 conceal themselves, and these are usually nauseous 

 to the taste. For instance, the gooseberry moth 

 caterpillar was given to frogs to eat, whereupon 

 they " sprang forward and licked them eagerly into 

 their mouths ; no sooner had they done so than 



