AKT. 1) TWO-WINGED FLIES OF TRIBE MILTOGRAMMINI ALLEN 81 



but largely below it. Posterior spiracles located on the upper sur- 

 face of the pit, and provided with three small, straight, nearly ver- 

 tical slits. Anal opening on the ventral surface of the puparium. 



This species is not known to be attracted to flowers, but has been 

 observed feeding on foliage and dry leaves smeared with honeydew. 



Prof. J. B. Parker has secured some interesting notes on the biology 

 of HilareUa Mlarella at Washington, D. C. In one instance, on July 

 11, 1914 (Parker Note 45), a female of Sphex extrematata, var. -picti- 

 pennis Walsh, was observed entering her burrow with a caterpil- 

 lar. As she emerged a small fly alighted at the edge of the vertical 

 opening of the burrow and deposited several maggots on the edge. 

 These wriggled over the edge and dropped to the bottom. Three 

 maggots were counted but there may have been more. A fly, ap- 

 parently the one which deposited the maggots, was captm^ed. The 

 wasp, after closing the entrance, was also captured. On the following 

 day the nest was dug up. A single caterpillar w^as found about an inch 

 below the surface. No egg of the wasp was present, but four dip- 

 terous maggots were on the outside, and subsecjuent results indicate 

 that four more must have been on the inside. On July 15 the 

 maggots had completely devoured the caterpillar and had buried 

 themselves in the sand of the breeding cell. On July 16 eight puparia 

 were present, from w^hich four flies issued on August 1 and three 

 others on August 2. In another instance (Parker Note 55) a fly was 

 captured wdiich had persistently attempted to place its maggots on a 

 caterpillar that Psammopliila violaceipennis Lepeletier had captured 

 and was dragging to her nest. 



M. R. Smith has also reared the fly from the nest of Sphex extre- 

 matata, var. pictipennis, at Agricultural and Mechanical College, Mis- 

 sissippi. In the instance under his observation, he feels quite certain 

 that the adult fly deposited active maggots on the paralyzed cater- 

 pillar when it was laid aside by the wasp preparatory to opening its 

 nest. Since the caterpillar from which the flies were reared was dug 

 up immediately after the nest had been closed by the wasp, and 

 since wdth this species of wasp only one caterpillar is placed in a nest 

 and the bui row is carefully closed both before and after depositing the 

 prey, and as in this case the fly did not enter the burrow, apparently 

 no other opportunity to establish its progeny was offered the fly than 

 that furnished by the wasp in dropping its prey to open the nest. 

 One nest containing a caterpillar of CMoridea ohsoleta was dug up, 

 and the following day three dipterous maggots were observed working 

 upon it. AU of them pupated, and from the puparia one adult of 

 HilareUa Jnlarella issued. 



