THE STATE ENTOMOLOGIST. Ill 



this as the fate of the potato bug for the present, and 1 will write you 

 again in a month, or as soon as I get additional news from him. 



'• The Illinois correspondent of the Country Gentleman, writing 

 from Champaign county, says: 



"Those plowing old potato ground where these creatures operated 

 extensively last year, find the ground full of the dormant wretches. 

 We, at Muscatine, Iowa, will lend them our Benson's Horse Power 

 Potato Bug Killer, but we can't spare our lady bugs." 



The following enemies of the Colorado Potato beetle, are among 

 the most prominent which have been instrumental in checking its 

 ravages during the past summer. 



THE COLORADO POTATO-BEETLE PARASITE— Lydella doryphora, N. Sp. 

 (Diptera Tachinidfc.) 



This fly (Fig. 48) has probably been more efficient in checking it 

 than any one other insect, at least in our 

 own State. Until last year no parasitic in- 

 sect whatever was known to prey inter- 

 !^ nally upon it, but this fly destroyed fully 

 , ten per cent, of the second brood and fifty 

 per cent, of the third brood of potato- 

 beetles that were in my garden. It bears 

 a very close resemblance, both in color 

 and size, to the common house fly, butis 

 readily distinguished from the latter by 

 its extremely brilliant silver-white face. 

 It may be seen throughout the summer months flying swiftly from 

 place to place, and deftly alighting on fence or wall, where, basking 

 in the sun, its silvery face shows to good advantage. As with the rest 

 of the family to which it belongs, the habit of the female is to attach 

 a single egg externally to the body of the Potato-beetle larva. This 

 egg subsequently hatches into a little footless maggot, which burrows 

 into the body of its living victim, and eventually destroys it, but not 

 until it has gone underground in the usual manner. The victimized 

 larva in-tead of becoming a pupa, and eventually a beetle, as it would 

 have done had it not been attacked, begins to shrink as soon as it en- 

 ters the ground, and gradually dies; while inside its shriveled skin 

 the parasitic maggot contracts into a hard brown pupa, and in due 

 time issues forth in the shape of the fly which I have figured. I am 

 indebted to Mr. Wm. LeBaron, of Geneva, Illinois, lor the generic de- 

 termination of this fly. It belongs to the genus (or sub-genus; Lydella 

 Macquart, and is very closely allied to lachina proper, with which it 

 could properly be united, did not the great number of species require 

 a division as a matter of necessity. I subjoin a more detailed des- 

 cription of the fly : 



Lydella dokyphor,*:, New Species. — Length 0.25. Alar expanse 0.48. Antennae black. 

 Palpi fulvous. Face silvery white. Front si.very, tinted with pale golden-brown, with a broad 

 middle stripe black. Thorax cinereous with imperfect black stripes. Abdomen black and silvery- 



