Feb. 2. I920 Life History of Euhiomyia calosomae 489 



upon which earth was placed. Two or more specimens of Calosoma 

 were inclosed with some caterpillars for food. The flies were offered 

 sugar and water absorbed in a sponge and also sprayed on foliage. About 

 372 flies were used in the experiments, but no copulation or oviposition 

 was observed that year. 



In 1 91 6, although fewer flies were reared than in 191 5, a show case was 

 modified so as to answer for a breeding cage. It measured 31K by 

 21K inches and was 11 inches deep. The glass was removed from the 

 ends and fly screen substituted. The top and one side were of glass, 

 and the other side contained two sliding doors. Shallow pans of earth 

 were inclosed for the beetles, and flowers and sweetened water for the 

 flies. More freedom was given the host and its parasites, and better 

 results attended these efforts. Fertile eggs were secured in 191 6, 1917, 

 and 1918. 



The beetles parasitized in the breeding cage were transferred to large 

 -glass battery jars partly filled with loam for hibernation and also to box 

 cages set in the ground. These cages were provided with a top and 

 bottom of copper ware of fime mesh. 



PARASITES BRED FROM FIELD COLLECTIONS OF CALOSOMA SYCO- 



PHANTA 



During the seasons of 1915, 1916, 1917, and 191 8 large field collections 

 of beetles were made in eastern Massachusetts where the species had 

 become abundant. These collections were made for the dual purpose 

 of securing specimens for colonization in new and outside territory in- 

 fested with Porihetria dispar and of studying the parasite attacking them. 

 During 1915, 15,322 beetles were collected, and 204, or 1.3 per cent, died 

 of parasitism. At that time such large numbers were collected for 

 colonization that it was impracticable to hold all of them in cages until 

 all died that would have succumbed to parasitism, hence the percentage 

 is probably slightly lower than it normally should be. During 191 6, 465 

 beetles were collected. These were fed in cages long enough for all 

 those affected vv^ith parasites to have died. Sixteen beetles, or 3.4 per 

 cent, died from parasitism. During 191 7, 4,679 beetles were collected 

 and confined in large cages. Sixty-three of these, or 1.3 per cent, died 

 from parasitism. Six hundred of this lot were forwarded to Mr. L. S. 

 McLaine, of the Department of Agriculture, Dominion of Canada, 

 located at Frederickton, New Brunswick, for colonization. Mr. McLaine, 

 upon request, held and fed the beetles in cages until July 21. During 

 this period 20 died, and 18 flies issued from the 20 dead. This would 

 indicate that from 6 to 10 died of parasitism, since an average of about 

 3 flies usually issue from each beetle. A total of 6,072 beetles were 

 collected in 191 8, and only 16, or 0.26 per cent, died from parasitism. 



During these years the dead beetles collected in the field or dying in 

 the cages at the laboratory were dissected or isolated in vials or jars for 

 issuance of the parasites. The data collected in 191 5 showed that the 



