222 The Irish Naturalist. November, 



The researches of I^euckart 3 and Pratt 4 have made known the 

 details of internal transformation, and have shown that the 

 abnormal process in the Pupipara is readily derivable from 

 the ordinary metamorphosis of the higher Diptera. But the 

 outer structure of the puparium seems well worthy of study, 

 and I am glad to be able to contribute a few details on that of 

 the " Grouse-fly," Ornithomyia avicularia. 



It is now well known that the structure actually " laid " by 

 the mother-fly is a mature larva, of which the hind -region 

 surrounding the stigmata is already hard and chitinous, while 

 the greater part of the body remains white and membranous. 

 As the larval skin hardens to form the puparium the whole 

 surface becomes firm and dark in texture. This process in 

 Hippobosca equina is well figured in De Reaumur's " Memoir," 

 and quite recently Miss Ormerod published a short descrip- 

 tion and drawing 5 of the newly-born larva of Ornithomyia 

 avicularia. She contented herself, however, with indicating 

 the general form of the body, and of the area around the 

 stigmata. 



In the spring of last year my friend, Mr. G. P. Farran, 

 brought me from Templeogue, Co. Dublin, two females of 

 O. avicularia which he had taken the previous evening from a 

 dead Kestrel. The flies had been imprisoned in a glass tube 

 during the night, and when examined in the morning this 

 tube was found to contain two small shining black ovoid 

 bodies, while the abdomens of the flies, greatly distended, so 

 Mr. Farran told me, when taken from the host, had a shrivelled 

 aspect. No doubt could be entertained that during the night 

 the flies had brought forth larvae which had already become 

 completely changed to puparia. These were put on one side 

 for future examination, and when I looked at them in the 

 summer of this year I found that from one a fly had partly 

 emerged, but had died without being able to extricate itself 

 completely (fig. 7). 



3 R. Iveuckart. Die Fortpflanzung und Entwickelung der Pupiparen. 

 Abh. Naturforsch. Gesellsch. Halle, vol. iv., 1858, pp. 145, 226, pi. 3. 



4 H. S. Pratt. Beitrage zur Kenntnis der Pupiparen. Arch.f. Naturgesch. 

 Jahrg. lix., 1 Band, 1893, pp. 151-200, taf. 6. 



5 E. A. Ormerod. Report of Injurious Insects, &c, 1899. London 1900 

 (pp. -63) 



