THE CANTHARIDES. 
135 
When it. is fully grown, it stops up the open end of its case, 
and changes to a pupa, and afterwards to a beetle within it, 
and then gnaws a hole through the case, in order to escape. 
As none of these insects have been observed to do much 
injury to plants in this country, I shall state nothing more 
respecting them, than that Clythra dominicana u inhabits the 
sumach, C. quadri guttata 15 oak-trees, Chlamys gibbosa low 
whortleberry bushes, Cryptocephalus luridus the wild indigo- 
bush, and most of the other species may be found on different 
kinds of oaks. 
Although the blistering beetles, or Cantharides (Cantha- 
himdas), have been enumerated among the insects directly 
beneficial to man, on account of the important use made of 
them in medical practice, yet it must be admitted that they 
are often very injurious to vegetation. The green Canthar- 
ides, or Spanish flies, as they are commonly called, are found 
in the South of Europe, and particularly in Spain and Italy, 
where they are collected in great quantities for exportation. 
In these countries they sometimes appear in immense swarms, 
on the privet, lilac, and ash ; so that the limbs of these plants 
bend under their weight, and are entirely stripped of their 
foliage by these leaf-eating beetles. In like manner our 
native Cantharides devour the leaves of plants, and some- 
times prove very destructive to them. 
The Cantharides are distinguished from all the preceding 
insects by their feet, the hindmost pair of which have only 
four joints, while the first and middle pairs are five-jointed. 
In this respect they agree with many other beetles, such as 
clocks or darkling beetles, meal-beetles, some of the mush- 
room-beetles, Hat, bark-beetles, and the like, with which they 
form a large and distinct section of Coleopterous insects. 
[ 14 Clythra ( Coscinoptera ) dominicana. — Lec.] 
[ 15 Clythra {Bahia) quadri guttata. — Lec.] 
