492 Journal of Agricultural Research voi. xviii, No. 9 



male lived 4 days, one male 5 days, one female 9 days, and one female 

 16 days. 



Another similar experiment was started on July 14, 191 5, with eight 

 flies inclosed in a lamp chimney. The length of life was as follows : One 

 fly lived 7 days, one fly 8 days, two flies 1 1 days, one fly 23 days, one fly 

 24 days, one fly 26 days, and one fly 30 days. The minimum in this 

 experiment was 7 days and the maximum 30 days, or an average of 18. 



HIBERNATION 



Euhiomyia calosomae hibernates in the second larval instar (PI. 58, D) 

 within the body cavity of Calosoma adults. The small maggot, after 

 hatching, enters the body probably through the spiracles, for the first- 

 instar larva is found attached to the tracheal branches in the metatho- 

 racic region. It feeds in this location for a few days and enters the 

 second instar about the time the beetles enter the earth for hibernation. 



Four eggs were deposited upon an adult in the breeding cage on July 

 26, 1917, and the beetle was immediately transferred to a jar of earth 

 into which it descended for hibernation about August i , The beetle was 

 dissected February 9, 191 8, and was found to contain four second-ins tar 

 larvae securely attached posteriorly to the tracheal system of the beetle 

 and inclosed in a tracheal funnel. The location of these larvae was within 

 the body cavity above the metasternum and lying longitudinally with 

 the anal stigmata pointing toward the anterior end of the beetle. 



When spring arrives the parasitized beetles, pressed by weakness from 

 loss of blood and fats, begin early in the season to wend their way 

 upward to the surface of the ground in search of food. The parasites 

 are probably feeding all the while during this activity, further weakening 

 their host; and death results in the course of two or three days. The 

 dead parasitized beetles are usually found on the surface of the earth. 

 It is quite probable that they sometimes die before wholly emerging, 

 but it has been proved by laboratory experiments that flies issuing under 

 such conditions are capable of forcing their way through a few inches of 

 earth without harm to themselves. 



The parasitized beetles emerged on May 25, 191 6, and about June i, 

 1 91 7; but the maximum normal field emergence of specimens of Calo- 

 soma sycopJiania was about June 10 to 15 during those years. 



NUMBER OF GENERATIONS AND PERIOD OF EMERGENCE OF FLIES 



Euhiomyia calosomae passes through two complete generations a year 

 on Calosoma sycophanta as a host and in some instances, where beetles 

 remain active for a period of one week or more after becoming para- 

 sitized, through a partial third generation. On May 27, 1915, H. W. 

 Allen collected a female of Euhiomyia calosomae at Lunenburg, Mass. 

 This is the earliest known seasonal record of issuance of adults in the 



