82 



THE HOUSE FLY AND ITS ALLIES. 



87. Larva of a 

 Sargus-like fly. 



cies, the M. vomitoria, is the Meat fly. Closely allied are the 

 parasitic species of Tachina, which live within the bodies of 

 caterpillars and other insects, and are among the most beneficial 

 of insects, as they prey on thousands of injurious caterpillars. 

 Another fly of this Muscid group, the Idia 

 Bigoti, according to Coquerel and Mondiere, 

 produces in the natives of Senegal, hard, red, 

 fluctuating tumors, in which the larva resides. 

 Many of the smaller Muscids mine -leaves, 

 running galleries within the leaf, or burrowing 

 in seeds or under the bark of plants. We have 

 often noticed blister-like swellings on the 

 bark of the willow, which are occasioned by a 

 cylindrical, short, fleshy larva (Fig. 88 a, much 

 enlarged), about aline in length, which changes 

 to a pupa within the old larval skin, assuming 

 the form here represented (Fig. 88&), and about 

 the last of June changes to a small black fly 

 (Fig. 88), which Baron Osten Sacken refers doubtfully to the 

 genus Lonchaaa. 



The Apple midge frequently does great mischief to apples 

 after they are gathered. Mr. F. G. Sanborn states that uine- 

 tenths of the apple crop in Wrentham, Mass., were destroyed 

 by a fly supposed to be the Molobrus mali, or Apple midge, 



described by Dr. 

 a Fitch. "The 



eggs were sup- 

 posed to have 

 been laid in 

 fresh apples, in 

 the holes made 

 by the Coddling- 

 m o t h (Carpo- 

 88. Willow Blister fly. capsapomo- 



nella), whence the larvae penetrated into all parts of the apple, 

 working small cylindrical burrows about one-sixteenth of an 

 inch in diameter." Mr. W. C. Fish has also sent me, from 

 Sandwich, Mass., specimens of another kind of apple worm, 

 which he writes has been very common in Barnstable county. 

 "It attacks mostly the earlier varieties, seeming to have a par- 

 ticular fondness for the old fashioned Summer, or High-top 



