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 3^ drachm. 



Zinc oxide ]4 oz. 



Lime water 8 oz. 



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 

 THEIR 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 

 42a. Blister bee- poisonous blood plasma. Such forms have been well 

 designated by Taschenberg as cryptotoxic (XPUXTO<; = 

 hidden). We shall consider a few representative forms. 



The Blister Beetles Fore- 

 most among the cryptotoxic 

 insects are the Meloida or 

 "blister beetles," to which the 

 well-known "Spanish fly" (fig. 

 4 2 a), 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 Robert, the amount 

 of this varies in different species 

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

 dry weight of the beetle. 



42&. An American blister beetle. Meloe an- 

 gusticollis. Photograph by M. V. S. 



