214 



Annals Entomological Society of America [Vol. VI, 



The young larvae appear in late May and early June. The 

 larvae live in vertical burrows which end at the surface in a 

 smooth circular opening (Fig. 2; also bh of Fig. 16, p. 221), They 

 pass through three instars, the first two of which are about 

 one month each in duration. The third and last stage is 

 reached in the last part of July, in August and early Septem- 

 ber. These stages pass the winter in the burrows, appearing 

 at the surface in May, and feeding until from June 20 to July 

 20. Each larva then digs a pupal (pch of Fig. 16, p. 221) 

 burrow filling the main burrow at the same time. The larva 

 remains quiet in this cavity for about three weeks when it 

 pupates if it has not been parasitized, and emerges in August, 

 making its way to the surface about three weeks later. 



Fig. 1. The adult fly about twice natural size. 



Fig. 2. A burrow of a larva of the second instar of C. scutellaris Lecontei, about 

 natural size. 



Fig. 3. General habitat of C. scutellaris Lecontei at a point where the fly was 

 observed ovipositing, and the kind of situation in which the parasite 

 is most abundant. The burrows of two larvae of the host are in the 

 last instar, and are visible above the small arrows. 



