COLEOPTERA. 587 



than the wing-covers, which are soft and flexible ; the legs 

 are long and slender; the hind tarsi are four-jointed, and 

 the fore and middle tarsi are five-jointed. 



These beetles are found on foliage and on flowers, on 

 which they feed in the adult state ; some of the species are 

 very common on goldenrod in the autumn ; and several 

 species feed on the leaves of potato. 



The blister-beetles are so called because they are used 

 for making blister-plasters. The beetles are killed, dried, 

 and pulverized, and the powder thus obtained is made into 

 a paste, which when applied to the skin produces a blister. 

 The species most commonly used is a European one, com- 

 monly known as the Spanish-fly; but our American species 

 possess the same blistering property. 



The transformations of blister-beetles are remarkable ; 

 not only do these insects undergo wonderful changes in 

 form, but the number of these changes is greater than is 

 usual with insects. On this account their mode of develop- 

 ment is termed hypermetamorphosis. 



The beetles lay their eggs in the ground. The newly- 

 hatched larva is active, running about in search of its food, 

 which consists, in some species, of the eggs of locusts, in 

 others of the egg and honey of some solitary bee. 



In the case of those species that live in the nests of bees 

 the larva finds its home in a curious way. Instead of hunt- 

 ing for a nest it merely climbs a plant, and remains near a 

 flower till it has a chance to seize hold of a bee visiting the 

 flower. The larva clings to the bee until she goes to her 

 nest, then, letting go of the bee, it remains in the cell and is 

 shut up there with the egg of the bee and the store of food 

 which she provides for her young. The beetle larva then 

 devours the egg ; after which it moults and undergoes a 

 change of form, becoming a clumsy creature, which feeds 

 upon the honey. Several other changes in form occur be- 

 fore the beetle reaches the adult stage. 



The wonderful instinct by which the larvae of these 



