THE BITING HOUSE FLY 245 



eight days. In the puparium the insect remained from 

 nine to thirteen days. The development of the species 

 is therefore slower than that of the true house fly. It 

 is Newstead's opinion that the winter is passed chiefly 

 in the pupal condition. Packard (1874) describes the 

 pupa of this species. 



The extraordinary effects of numbers of the bites of 

 this fly, indicated in the account of the epidemic of 

 1908 in Argentina, cannot be exaggerated. Cattle and 

 horses suffer severely from these bites when the in- 

 sects are numerous. Mr. T. J. Bold, in the Entomolo- 

 gists' Monthly Magazine for 1865, p. 143, gives an 

 account of the condition of these animals at Long 

 Benton in September of that year. Fourteen cows 

 were under treatment by a veterinary surgeon at one 

 time. The animals were generally bitten on the out- 

 side of the legs, on the shoulders, and, rarely, on the 

 neck. In severe cases the joints were so much swollen 

 that the animals could not bend their legs to lie down, 

 and the swelling from the inflammation was so great 

 that the outer skin cracked and the hair fell off. It 

 is stated that the flies appeared to prefer the knees and 

 upper portion of the foot of the cow, frequently crawl- 

 ing from them to the hands of the veterinary, but their 

 bites had no bad effect on him. It would seem from 

 this as though animals are more susceptible than man. 



This biting fly has often been thought to be a dis- 

 ease carrier and especially of blood parasites of do- 

 mestic animals. The evidence for and against has been 

 carefully considered by Austen (1909, p. 153), who 



