THE PARASITES OF MAN. 45 
simply the carriers of tbe parasites; others live upon surplus 
food or upon food not entirely consumed by their hosts; still 
others make use of the host himself, by eating part of the 
same; and a few not satisfied with being such contemptible 
beings, commit even murder by enfeebling and killing the 
host that provided them with food and shelter. 
Farmers have to fight almost constantly against all 
kinds of parasites, since otherwise their hopes of rich returns 
for their labors in the fields would come to naught. And yet 
how few farmers realize how much they lose year after year 
by the inroads of such pilfering beings, simply because these 
live a hidden life not easily observed. They, with other ene- 
mies such as plant-eating insects, take every year the lion’s 
share of our crops, and some vegetable parasites, such as 
rusts, smuts, and similar lowly organized plants, not infre- 
quently destroy all the plants so carefully planted and culti- 
vated by the farmer. Some still smaller parasites, as certain 
kinds of bacteria, cause diseases among man and domestti- 
cated animals, and frequently to such an extent that they 
are swept away or decimated overa large area. Other para- 
sites live inside man and his two or four-footed friends, and 
cause great losses, by weakening or even killing them. Still 
others, less dangerous but equally annoying, and in extreme 
cases as bad, live upon the various kinds of domesticated 
animals, and cause all sorts of trouble and diseases. And 
even man, the crown:of creation, is not entirely immune; 
even he, not excepting her, has been seen—in other States of 
course—to scratch himself, or to investigate with great in- 
dustry the heads of her promising offspring. 
All parasites dwell either upon the bodies of their hosts 
or inside of them, for a short time or permanently, and as 
they subsist upon substances of great and even vital import- 
ance to the latter they cause more or less serious disturb- 
ances, even fatal diseases. Such parasites belong either to 
the vegetable or to the animal kingdom. It is not the in- 
tention to discuss the former, or all of the latter, as being 
foreign to an entomological report. Only such parasites will 
be discussed as are either genuine insects, or so closely allied 
to them as to be usually considered as such. ‘They will be 
