q5 transformations of insects. 



many species of the family have been used in the healing art 

 ever since the time of Hippocrates and Aretaeus. The integu- 

 ments of these insects contain the blistering substance, and as this 

 is so much used a great deal of trouble has been taken to 

 investigate their habits and metamorphoses, but without much 



success. 



The oil beetles belong to this family, although they are 

 apparently very differently formed to the brilliant blistering fly. 

 These oil beetles, which belong to the genus Meloe, emit an 

 oily liquor like those just mentioned, and it has vesicating 

 properties. The insects do not fly, they have no wings, and 

 their elytra are very short, their bodies being clumsy, heavy, 

 and soft. They crawl over low plants and grasses, and feed 

 upon wild buttercups, and they are apt to be eaten by cattle, 

 whose mouths soon become much afl-ected. The metamorphoses 

 of some of the CantharidcB have been very ably investigated by 

 George Newport and other naturalists. Thus, in the year 1700, 

 Goedart collected the eggs of some species of Mcloc, and ob- 

 tained some young larv^. Later De Geer did the same, but m 

 both cases the larv^ perished immediately after their birth, and 

 the observations of the two authors were forgotten. In 1802, 

 Kirby a celebrated English entomologist, found a small insect 

 which' resembled the larv^ described by Goedart and De Geer 

 upon some Hymenoptera related to the bees, and belonging to 

 the genus Andrena, or solitary bees. He thought they were 

 parasites In 1828 Leon Dufour found an insect which probably 

 belonged to a parasite of the same kind as those just noticed. 

 He considered it to be a new species, and he called it by the 

 name of Triongullnus. Many observers managed to hatch the 

 ecTgs of Meloe, Spanish flies, and of species of the genus Sitaris, 

 which belongs to the same family, but does not possess blistering 

 properties, but they did not get further than the point obtained 

 by Goedart in the year 1700. After a time, however, it became 

 evident that the young larvae hooked themselves on, whenever 

 they had the opportunity, to other insects provided with wings, 

 and especially to the nest-making Hymenoptera; and Victor 

 Audouin found some full grown and adult individuals of species 

 of Sitaris in the nests of the solitary bees. There appeared. 



