36 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



puparia were four inches below the surface of the ground. The soil 

 was a sandy loam. The puparia were put in a breeding cell. On 

 July 4, 1914, all flies had emerged." 



The writer secured the following information in rearing from 

 Blcyrtes quadrifasciata. A female was noted intently watching the 

 wasp builcUng its burrow and was captured and identified. A single 

 nest from a lot of several collected in this colony was found to be 

 infested with six maggots, all of which proved to be trilineata. The 

 development of the maggots in this nest proved to be almost identical 

 with that of the larvae of S. vigilans, previously discussed. The 

 maggots remained undiscovered until after the wasp egg had hatched, 

 but the grub of the wasp failed to develop since it was soon over- 

 whelmed by the rapidly growing Dipterous larvae. In this case, all 

 the stores of the wasp were consumed, the maggots spending the 

 greater part of their developmental period as Sarcophagidlike scav- 

 engers in the midst of the decomposing bodies of the bug nymphs. 

 The larval period from the time the nest was collected to the formation 

 of the puparium was four to five days. Since the nest was not col- 

 lected at actual larviposition time, the total larval period may have 

 been a day or two longer. Puparia were formed in damp sand be- 

 neath the debris of the nest. The pupal period ranged from eight to 

 eleven days, four of the six that were reared emerging on the ninth day. 



Regarding the establishment of parasite on host, the writer has 

 made no direct observations. Curran states that S. trilineata females 

 poise over the entrance of the burrow and drop eggs directly into it 

 as the wasp drags her prey down into it. The white objects seem 

 dropping into the burrow, wliich lie plainly states were not recovered 

 for closer examination, v/ere in all probability active, naked larvae, 

 such as are readily demonstrated in the uterus of this and all nearly 

 related species. The writer has dissected several gravid females 

 of S. trilineata, in all of which the uterus was filled with large white 

 maggots not exceeding 75 in number. 



Several workers have noted the presence of annoying and persistent 

 Dipterous parasites in connection with their studies of the bionomics 

 of various fossorial Hymenoptera. Most of them have reared these 

 parasites in sufficient numbers to be impressed with the idea that 

 they constitute a heavy drain on tlie economy of the wasps. Several 

 have noted that the wasps frequently turn on their wary pursuers, 

 and attempt to drive them away. None, however, seem ever to have 

 observed the wasps catching these elusive little flies. But observa- 

 tions made by tlie writer indicate that one species of wasp not only 

 catches these flics but uses them to provision its nest. Several 

 nests of Bemhix spinolae were dug out at Columbus, Ohio, in the 

 summer of 1021, whieli were found to contain the dismembered cliitin- 



