382 A COMPENDIUM OF 
potato fly, because it is found on the green and 
flowering tops of that vegetable. The Spanish 
fly, the one under discussion, is a native of central 
and southern Europe, and is found abundantly 
on the trees and shrubs belonging to the natural 
order of Caprifoliaceee and Oleacee. They 
are obtained for the drug market by beating the 
branches of the trees or shrubs. The insects 
are caught upon cloths placed beneath for that 
purpose, They are then plunged into vinegar, 
or else placed in sieves and exposed to the ac- 
tion of turpentine and the vapor of vinegar, hot 
water, etc. The Spanish fly is of a bronze or 
copper-green color, with brown, transparent 
wings, about 1 inch long (25 millimeters) and 
¥ inch broad 6 millimeters) ; the odor is strong 
and unpleasant. The powder presents a gray- 
ish-brown appearance, showing many green and 
bronze-like looking particles. Cantharides con- 
tains acetic and uric acids, phosphates of lime, 
magnesia, fatty matter, oil, and cantharidin, 
which is the active principle, an intermediate 
substance between a resin and volatile oil, crys- 
tallized in colorless scales, and composed of C, , 
H,, 0,; soluble in alcohol, ether, volatile oils, 
chloroform, and some of the fats. 
The potato fly must not be confounded with 
the small potato bug. The formeris about the 
size of the Spanish fly, with black wing cases, 
striped with yellow along the margins, with a 
yellow stripe along the back. The bug is small, 
and is dotted with yellowish-red and black spots, 
and has none of the qualities of the species. 
The medical properties of the Spanish fly are 
