54 



Poisonous Arthropods 



In the brown-tail district, there are many proprietary remedies of 

 which the best ones are essentially the following, as recommended 

 by Kirkland (1907): 



Carbolic acid 

 Zinc oxide . . . 



Lime water. . 



drachm. 



!4 oz. 

 8 oz. 



42a. Blister bee- 

 tle. 



Shake thoroughly and rub well into the affected parts. 



In some cases, and especially where there is danger of secondary 

 infection, the use of a weak solution of creoline (one teaspoonful to a 

 quart of water") , is to be advised. 



Vescicating Insects and those Possessing Other Poisons in 

 THEm Blood Plasma 



We have seen that certain forms, for example, the 

 poisonous spiders, not only secrete a toxine in their 

 poison glands, but that such a substance may be ex- 

 tracted from other parts of their body, or even their 

 eggs. There are many insects which likewise possess a 

 poisonous blood plasma. Such forms have been well 

 designated by Taschenberg as cryptotoxic (xpu'7:':o? = 

 hidden). We shall consider a few representative forms. 



The Blister Beetles— Fore- 

 most among the cryptotoxic 

 insects are the Meloidce or 

 "blister beetles," to which the 

 well-known "Spanish fly" (fig. 

 42a), formerly very generally 

 used in medical practice, be- 

 longs . The vescicating property 

 is due to the presence in the 

 blood plasma of a peculiar, 

 volatile, crystalline substance 

 known as cantharidin, which is 

 especially abundant in the repro- 

 ductive organs of the beetle. Ac- 

 cording to Kobeft, the amount 

 of this varies in different species 

 from .4 or .5% to 2.57% of the 



(\rv wpicrht nf thp hpptlp *^*- ^^ American blister beetle. Meloe an- 



ary weignt 01 tne oeeue. gusticoius. Photograph by m. v. s. 



