muih: two new species of ascodipteron. 357 



opening of the "nutriment" gland. The appearance of the contents 

 of these glands and the contents of the stomach are the same under 

 a lens of high power, and they have a similar chemical reaction. 



The puparium. The full-grown larva is ejected from the uterus, 

 falls to the ground and pupates where it falls. At first pearly white, 

 it soon turns yellow, and in about an hour hardens to a dark brown 

 puparium, of similar size and shape to the larva. No anterior spir- 

 acles, or "horns," appear, but the thoracic tracheae of the pupa are 

 attached to two spots on the operculum, in a similar position to the 

 anterior pupal "horns" common to many of the Cyclorrhapha. The 

 operculum is large, the posterior margin running in a curve across the 

 dorsal surface, about one third down, and continuing in a curve to 

 the anterior edge, where it is slightly emarginate. There is no line 

 of dehiscence running ventrically. 



The position of the head of the male pupa is normal, but its small 

 size compared to the great operculum would suggest a ptilinum being 

 of little use. In the female the enormous labium is bent under and 

 rests on the sternum, a position it cannot take up when hatched and 

 hardened. Part of the notum and the face and frons are brought in 

 contact with the inner surface of the operculum, and it appears to be 

 the distention of the membrane, especially between the gena and 

 face and frons, that forces it off. The pupa state lasts about thirty 

 days. 



The puparia of the two species of Nycteribiidae that I know differ 

 very considerably from that of Ascodipteron. In P. progressa the 

 full-grown larva, when passing out of the uterus, becomes greatly 

 flattened, especially on the ventral surface, and is held by its anterior 

 end for a short time between the external flaps of the vagina, its 

 ventral surface being pressed against the skin of its host, generally 

 near the junction of the wing-membrane with the body or limb. The 

 chitinous exudation that covers the soft larval skin, to form the 

 puparium, first appears along the edges of the flattened ventral sur- 

 face and fastens it to its host, then covers the dorsal surface, but does 

 not appear on the ventral side, that side remaining a soft membrane 

 through which, if carefully detached from the host, the pupa can be 

 seen developing. The larval spiracles remain distinct and stand up 

 above the surface. No anterior pupal spiracles, or "horns" appear, 

 but the pupal thoracic tracheae are attached to two spots on the inner 

 surface of the operculum, and can be faintly discerned externally. 

 The operculum is large, the posterior edge curving across the dorsal 

 surface near the middle, slightly in front of the anterior spiracles, 



