II^SECTS INJURIOUS TO COTTOX. 193 



brood as early as 1847. The eggs of these insects are laid 

 upon the caterpillars, and the maggots hatching from them 

 bore into the worm and there feed upon its tissues. It 

 transforms to a pupa as usual, but the pupa soon dies, and 

 large numbers are thus killed. Several similar parasites 

 prey upon the cotton-worm, among the more important of 

 which may be mentioned EiqAedrus comstockii. It is to 

 be regretted that we have no way of encouraging the good 

 work of these valuable parasites. But the common insec- 

 tivorous birds which eat large numbers of the worms, 

 especially when they are yet scarce in early spring, may 

 and should be protected by enacting and enforcing the 

 most stringent laws against their wanton destruction. 



Remedies. — Paris green is an effectual and now widely 

 used remedy for this pest. When the United States 

 Entomological Commission made their extensive investi- 

 gations of remedies for cotton-insects in the early 80's, 

 they devised some very tremendous apjiliances for spraying 

 this upon as many as sixteen rows at once. But such 

 machines have not proved practical, and it was found 

 useless to attempt spraying over four rows at once. In 

 fact they have never been used throughout the South in 

 other than in an experimental capacity. 



Besides the general use of the dry Paris green by dust- 

 ing it upon the plants as described below there have been 

 several important factors which have so worked against 

 the cotton-worm that the problem of keeping it in check 

 is now considered practically solved by many authorities. 



The most important of these, and a most beneficial 

 change as regarded from other than an entomological 

 standpoint, is the diversification and rotation of crops, 

 now coming to be more and more widely practiced by the 



