172 WILLIAM BRODBECK HERMS 



Zoology^ at Harvard University, Cambridge, Mass. The present 

 paper was practically completed in June, 1908, though not pre- 

 sented for publication till July, 1910. 



The species upon which observations were made at Sandusky 

 are Lucilia caesar Linn., Compsomyia macellaria Fabr., Sarco- 

 phaga sarraceniae Riley, and Sarcophaga assidua Walker. Where 

 there was such an abundance of food as at the Lake Laboratory 

 one might also have expected to find Calliphora vomitoria Linn., 

 but this species was rarely seen on Cedar Point in the neighbor- 

 hood of the Laboratory, during the period of observation. 



The very uniform surroundings and constant food supply 

 obtaining during July and August at Cedar Point (Herms, '07, 

 p. 74), together with the great warmth at this time of the year 

 resulted in a rapid sequence of broods and a remarkably regular 

 life histor}^ for each species (Herms, '07, p. 54). Irregularity is 

 rather the rule for situations removed from the beach (Herms 

 '07, p. 76), and this was particularly noticeable at Cambridge, 

 where, moreover, late autumn and winter conditions had to be 

 dealt with. Here, however, the flies were reared in a room where 

 the temperature was kept artificially high and by careful atten- 

 tion to the kind and quantity of food, a continuous colony was 

 established. Fish was invariably given as food for the larvae, 

 while the flies were kept well supplied with water, occasionally 

 sweetened with sugar. Notwithstanding the extreme care, the 

 same regularity for the various stages in the life history as ob- 

 served at Cedar Point was not secured in Cambridge. 



For experimental purposes the two species which deposit eggs 

 (Lucilia caesar and Calliphora vomitoria) were selected so that the 

 time of hatching could be recorded. The former was used at 

 Cedar Point and both species in Cambridge. It may be noted 

 here incidentally that Compsomjda macellaria, the screw-worm 

 fly, deposits eggs in the Southern States (Osborn, '96, p. 131), 



^The preparation of this paper and the critical observations herein described 

 were carried on under the direction of Professor G. H. Parker, to whom I wish to 

 express my sincere appreciation for help and advice. I am also indebted to Pro- 

 fessor E. L. Mark, Director of the Zoological Laboratory, for facilities kindly 

 furnished. 



