BLISTER BEETLES. 125 



dantly upon flowers on hedgebanks in all the southern 

 parts of the country. Numerous small species are 

 also exceedingly abundant in flowers, whilst others 

 are found upon and under the bark of trees; the 

 latter situation is also selected by some of the larvae, 



! whilst others are found in rotten wood. A few, like 

 Melo'e, are parasitic in their larva state, and amongst 

 these the curious Rhipiphorus paradoxus may be 



j noticed. This beetle, which measures from a half to 

 three-quarters of an inch in length, and has the an- 

 terior portion of the body thickened so as to give it 



I a singularly humped appearance, has the elytra gra- 



' dually tapering from the base to the apex, leaving the 

 wings exposed, and the antennae either serrated (in 

 the female), or doubly pectinated (in the male). Its 

 general colour is black, but the abdomen and elytra 

 are usually brownish yellow, with their tips alone 

 black ; the abdomen of the female is long and pointed, 

 so as to serve admirably as an ovipositor. The larva 

 lives as a parasite in the nests of the common Wasp, 

 where the perfect beetle may frequently be met with ; 

 it also occurs, like the rest of the tribe, upon floAvers. 

 Many of the beetles of this group, and amongst 

 them the common Melo'e above described, are endowed 

 with a peculiar property, which ranks them amongst 

 the most powerful of therapeutical agents ; this is the 

 power, when applied in the form of powder or tincture 

 to the skin, of raising blisters on the part with 

 which they are in contact. This faculty resides in 

 the soft parts of the insect, which contain a peculiar 

 substance called Cantharidine, and this appears to be 

 the vesicating principle. The species commonly em- 

 ployed in medicine is the Cantharis vesicatoria, a 

 beetle of a fine green colour, which is generally known 



