Feb. 2, I920 Life History of Euhiomyia calosomae 487 



ity of the larvae within the body cavity sometimes extend over a period 

 of one or more days after death of the host, which has been hastened 

 by dissection. 



The time required for the development of the larva from the hatching 

 of the egg to pupation ranges from 9 to 12 days during midsummer. On 

 June 23, 1917, Mr. F. W. Graham, of this bureau, collected an adult of 

 Calosoma sycophanta in the field bearing two eggs of the parasite. By 

 June 24, the chorion of the eggs had disappeared. On July 16 two 

 flies issued. Allowing 11 days for passing the pupal stage, 12 days 

 must have been required to pass the larval instars. In another instance 

 a beetle containing eggs of the parasite was collected in the field, and 

 a dissection of one of the eggs revealed an embryo. The same beetle 

 contained puparia 10 days later. Other breeding records indicate that 

 from 10 to 12 days are passed in the larval stages for the summer gen- 

 erations. 



PUPARIUM (PL. 59, a) 



Color reddish brown, form elongate, surface smooth when viewed with naked eye 

 but with aid of lens showing 6 to 18 broken annular rows composed of short, thick-set 

 spines to be seen on each segment (PI. 59, C). These rows appear as continuous, wavy, 

 broken lines, except with high power lens in which case the spines appear distinct 

 but \&TY closely set. Spine area sometimes covering one-half the surface of 

 the segments, but more prominent on anterior and posterior segments. Anal 

 stigmata (PI. 59, B) protruding above surface of puparium, inner margins almost 

 parallel, and each containing six radiating elongate slits. Puparia ranging in size 

 from 5 mm. long and 2.2 mm. broad to 8.2 mm. long and 4 mm. broad, or an average 

 for eight specimens of 6.6 mm. long and 3.1 mm. broad. 



The full-grown larva soon after accomplishing the killing of its host 

 enters the pupal stage. Some of the larvae in a host containing any 

 number of parasites up to 15 force a hole between the abdominal 

 tergites laterad and pupate just beneath or between the wings and 

 elytra. Of 620 puparia under observation in 191 5, 245, or 40 per cent, 

 pupated within the body cavity and 375, or 60 per cent, between the 

 dorsum of the abdomen and the elytra. The maggot pupates very shortly 

 after the death of its host, the period being hastened somewhat where 

 dissections are made which expose the tissue of the host and the mag- 

 got to the drying of the air. When the host is opened and contains 

 maggots practically full grown, pupation usually follows in from 10 to 

 36 hours. 



The time passed in the pupal stage ranges from 9 to 15 days. An 

 average of 12 days in midsummer was required in 191 5 by many speci- 

 mens under observation; iiK days were required in 191 6 and 11 days 



in 1917. 



DISTRIBUTION OF THE PARASITE 



Euhiomyia calosomae has been bred from collections of Calosoma 

 sycophanta from many towns in eastern Massachusetts and from one or 

 more towns in Maine, New Hampshire, and Rhode Island. Its known 



