CANTHARIDES 531 



shake out with successive portions of 30, 30, 20, and 20 c.c. of chloroform. 

 Recover the chloroform by distillation from a tared flask, dry the residue at 

 60, and wash first with 10 c.c. of a mixture of equal volumes of absolute alcohol 

 and petroleum spirit, and finally with petroleum spirit until the latter leaves 

 no appreciable residue on evaporation. Dry at 60 and weigh. 



Uses. Cantharides possess rubefacient and vesicant properties ; 

 given internally, the drug acts as an irritant poison. 



Varieties. The number of species of Coleoptera known to possess 

 vesicating properties is very large, but only a few are employed for 

 that purpose. The most important of these are Chinese blistering 

 beetles (Chinese cantharides), large quantities of which are regularly 

 imported. They are derived from two species, viz. : 



1. Mylabris sidce, Fabricius (M. phalerata, Pallas). This varies 

 from 12 to 30 mm. in length, and from 5 to 10 mm. in breadth. It 

 is black in colour, but the wing-cases are traversed by three broad, 

 brownish yellow bands. These bands bear 



black, bristly hairs which, however, are not 

 readily seen in the commercial drug, as most 

 of them have been broken off. The beetles 

 inhabit China, Bombay, Assam, &c. 



2. Mylabris cichorii, Fabricius, on the 

 average smaller than the foregoing ; it 



varies from 10 to 15 mm. in length, but is FIG. 246. Chinese blister- 

 marked with similar yellow bands, which, ing beetle, Mylabris sidce 

 however, are usually brighter in colour. The ( = M. phdlemta, Pall.), 

 chief distinction of this species lies in the 

 yellow downy pubescence with which the 



yellow bands are covered, the hairs on the black bands being black. 

 It inhabits China and eastern India. 



Chinese blistering beetles contain from 1 to 1-2 percent, of cantharidin 

 and form a useful source of this substance. 



In addition to these, several other blistering beetles find their 

 way occasionally to London, e.g. M. lunata, Pallas, and M. bifa- 

 sciata, Oliver, from South Africa, Epicauta gorhdmi, Mars, from 

 Japan, &c. 



C. quadrimaculatus (Mexican cantharides) have been imported 

 into Hamburg ; they resemble M . cichorii but have only two black 

 bands on the wing-cases. 



Admixture with (entire) exhausted beetles can be detected by the 

 deficiency in cantharidin and in fat. 



The drug is seldom adulterated, but accidental admixtures are 

 occasionally met with. 



1 Maisch's figure is apparently erroneously named M. cichorii. 



