496 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
could be certainly and safely attributed to climatic condition or to food. 
Lyperosia irritans Rob.-Desv. 
The horn fly confines its attentions exclusively to cattle on which 
it remains day and night with the exception that at intervals females 
with mature eggs dart down to fresh deposited cow dung for the purpose 
of oviposition. Having accomplished this function, they return to the 
cow where they either feed again or rest. 
When wild, gravid females are placed in breeding jars with fresh 
cow dung and fed defibrinated cow blood, some will remain alive for as 
long as 25 days, but cease laying eggs in from 3 to 5 days. The eggs 
hatch in 2 to 3 days, depending upon the temperature, and larval de¬ 
velopment follows. The minimum time required for a culture to com¬ 
plete its cycle from egg to adult was 11 days during an exceedingly hot 
wave in July. The maximum periods consumed during cooler weather 
were 20 days in May and 22 days in October. 
The first generation of reared Lyperosia , artificially fed, live from 
1 to 24 days, but lay no eggs. For this reason it has not been possible 
to rear this fly beyond the first generation of adults. 
In a previous publication (2) the matter of the resistance of Lyperosia 
to propagation under experimental conditions is discussed, after many 
attempts were made to induce the development of the reproductive 
organs of the first generation of reared males and females. It is difficult 
to conclude whether the food, the treatment, or both were responsible 
for this behavior. 
In concluding the subject of Lyperosia irritans it might be well to 
state that the sexes of the first generation of reared adults are numerically 
equal. 
Summary 
Simple, inexpensive and effective methods of rearing and handling 
large numbers of flies have been described in this article. A number of 
observations on the biology of Musca domestica , Stomoxys calcitrans 
and Lyperosia irritans are likewise included. 
Reference to Literature 
1. Hewitt, C. Gordon. The House Fly. 1914. p. 102. Cambridge, England. 
2. Glaser, R. W. The effect of food on longevity and reproduction in flies. 
J. Exp. Zo'dl ., 1923, xxxviii, 383-412. 
3. Newstead, R. On the life-history of Stomoxys calcitrans L. J. Econ. Biol., 
1906, i. 
4. Bishopp, F. C. The stable fly. U. S. Dept. Agric. Farmers' Bulletin 540, 1913. 
5. Bishopp, F. C. The stable fly. U. S. Dept. Agric. Farmers' Bulletin iogy, 1920. 
