116 FORTT-THIRD REPORT ON TEE StATE MvSEUM. [20] 



pictured in English works and in writings drawn from English 



sources. As much of our knowl- 

 edge of natural history, not many 

 years ago, was drawn from the 

 above sources, it is not uncom- 

 monly believed that we have the 

 same gad-fly in our country; but 

 while there are many species of 

 the TahanidcB which are at times 

 Fig. 8.-The ox gad-fly, t ab anus ^^^^^^^^^g^y^^^oying to our domestic 

 BoviNus. animals and to ourselves, the Taba- 



nus hovinus, fortunately, has not been intro- 

 duced among us. The species of this family 

 popularly known as "horse-flies" are injur- 

 ious through the severe bite that the fly 



inflicts preparatorv to, and during the opera- -,.„.,. j ^ . 



r r . i o f pj-q_ 9.— The ox ead-fly at 



tion of, her blood-sucking. Ouly the females rest. 



bite and feed on blood. The larval stage, in many cases, is passed in 



the ground. 



Drosophila sp. 



A Flour-paate Fly. 



(Ord. Diptera: Fam. Deosophilid^.) 



I send you by mail a package containing larvae cf a little fly, very 

 troublesome ax'ound my cellar and pantry. These were taken from 

 some paste that had been set aside for a short time. I could not 

 obtain any of the flies, but presume that they will be produced from 

 the larvse if they reach you in good condition. They are very partial 

 to anything in a state of fermentation, and if my pickled fruit or jam 

 begins to sour, they find the change in it before 1 do, and frequently 

 in a short time the entire top of the fruit seems alive with the larvse, 

 although they never penetrate deeply into the jar. Please tell me the 

 name of the insect, its habits, and history. O., Susquehanna, Pa. 



The flies have been bred from the larvse, sent in the paste, and they 

 appear to be a species of Drosophila, of which several species are 

 known to be attracted by the odor of fermenting substances. The 

 particular species of this minute fly is unknown to me. The pupa- 

 case is one-tenth of an inch in length, and the perfect insect has a 

 spread of wings of about one-eighth of an ifjch. Its large thorax 

 and small abdomen are of a dull yellowish color, and under a lens, 

 show a number of long, stout hairs; the wings are beautifully irides- 

 cent. These flies are so very small, that they would hardly be 

 noticed in the dim light of pantries and cellars.' ffhey are not of 

 the same species with those mentioned above as infesting pickled 

 fruit and jam when commencing to ferment. The latter, if they could 



