206 INSECT ARTIZANS AND THEIR WORK 



case has V-shaped ridges on one side, and is con- 

 structed of earth mixed with excrementitious 

 matter. As the grub grows it enlarges its case, by 

 scraping off portions of the inside with its jaws 

 and plastering more on the outside. It feeds on 

 the vegetable refuse of the nest, and also on the 

 pellets of the ants. When full-grown, the grub 

 fastens the mouth of the case to a bit of wood, or 

 other object in the nest, and, turning round inside 

 the case, changes to a chrysalis. When hatched, 

 the perfect beetle cuts a rim round the end of the 

 case with its jaws, forming a cap which it forces 

 off. It then crawls out of the nest and flies away." 



The brilliant little beetles of the genus Crypto- 

 cephalus that are frequent on flowers in sunny 

 places have a very similar habit of protection during 

 the grub stage, though they do not live in ants' 

 nests. Much the same may be said of Lamprosoma. 

 The Lily Beetle (Crioceris merdigera), whose larva 

 is destructive to the leaves of lilies, disguises itself 

 in the grub stage by covering its back with excre- 

 ment, which dries into a hard crust. The larvae 

 of the Tortoise Beetles (Cassida) have a similar 

 habit, though a less crude one. Nature has fitted 

 them with a fork-like extension of the hind body 

 which is carried turned up over their backs. Upon 

 this the excrement is spread and forms a sort of 

 umbrella which effectually disguises the insect. 

 An allied species, Dolicbotoma -palmarum, has a 

 more complicated instrument for the same purpose. 



Dr. Sharp describes a small beetle of tropical 



