54 mill am B. H 



erms 



(Ammophila and Panicum), while spreading and drying its wings. 

 When a high surf washes up a big carp into the tall grass, the 

 larvae after feeding on the carcass, migrate nearby and pupate. 

 When the imagines emerge the grasses are immediately resorted 

 to. This accounts for the presence of veritable swarms of flies in 

 a restricted area with no carcass near. Closer investigation will 

 almost invariably result in finding the bones and scales of some 

 large fish in close proximity. 



Most imagines reared in the laboratory emerged early in the 

 morning at the first break of day. In one instance a dozen pupae 

 were kept in one vial and out of these, seven adults emerged within 

 two minutes. 



Life Histories 



Lucilia caesar Linne (the common green flesh fly) : Eggs of 

 this species are cylindrical, rounded at both ends and slightly 

 curved, smooth and white. The average weight of one egg is 

 about O.I mg.^ 



Young larvae hatch in from eight to eighteen hours, depending 

 on the time of day the eggs are deposited. If deposited toward 

 noon the time will be lengthened, since observations show that 

 in such cases larvae do not emerge until the following morning 

 together with larvae coming from eggs deposited any time during 

 the afternoon. This period also undoubtedly varies with the age 

 of the ova at extrusion; /. e., depends on the length of time the ova 

 are retained within the female. 



The actual feeding period of the larvae varies as already indi- 

 cated from two to two and a half days and over. The interval 

 between migration and pupation varies from two to four days 

 and over, but the actual period of pupation is more constant — 

 about eight days. In the region studied all of the above periods 

 are generally quite regular, so that we may consider the period of 

 development from egg to imago as covering about fifteen days^ 

 varying a day either way. 



Sarcophaga sarraceniae Riley: This common large gray flesh fly 



^This weight was obtained by weighing two sets of fifty eggs, four or five hours old. The weight 

 of each set was 5 mg., and by throwing the two sets together 10 mg. resulted. Later five sets of twenty 

 eggs were treated in the same manner, resulting in a like average. 



