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 
