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STUDIES IN LIFE-HISTORIES OF AUSTRALIAN DIPTERA 

 BRACHYCERA. 



Part i. Stratiomyiidae. 



No. 1. Metoponia rubriceps Macquart. 



By Vera Irwin-Smith, B.Sc, F.L.S., Linnean Macleay Fellow of the 



Society in Zoology. 



(Plates xsvii.-xxviii., and 23 text-figures.) 



Introduction. 



During- the jiast twelve months I have had the opportunity of collecting, in 

 the neighbourhood of Sydney, many soil-inhabiting dipterous larvae, belonging, 

 for the most part, to the section Braehycera. Of these, I have succeeded in rear- 

 ing through to the imago, species of the families Stratiomyiidae, Mydaidae, Tab- 

 anidae, Asilidae, Therevidae, and Bombylidae. and to the pupal stage, many other, 

 as yet unidentified, species. 



Very little work has been d(UK% in any part of the world, on the early stages 

 of the Braohyoera, and the Australian forms have , been, up to the present time, 

 almost entirely unknown . The material now collected is therefore of considerable im- 

 portance, as affording an opportunity of studying the life histories of these files. 

 Many gaps yet remain to be tilled. In no case has it been possible to observe 

 all stages in the development, but it is hoped that the preliminary study of the 

 data obtained will prove useful as a basis for later, more extensive, investigations. 

 The present paper is intended as the first of a series dealing with the biology of 

 the group, arranged in the order of the families . 



The Stratiomyiidae, usually placed by taxonomists at the beginning of the 

 Braehycera series, are of special interest because of the peculiar, intermediate 

 position which they occupy, in their mode of development, between the two great 

 sub-orders of Diptera, distinguished Ijy Brauer under the names Orthorrhapha 

 and Cyclorrhapha. 



Although classed with the Orthorrhapha, and developing a more or less perfect 

 "pupa obtecta," they pass the entire pupal period within the last larval skin, 

 which constitutes a h&rd, protective case, recalling the "puparium" of the Cyclorr- 

 hapha. And the opening up of this case, at the emergence of the fly, is in the 

 form of a combination of the straight dorsal split of the Orthorrhapha, and the 

 anterior circular split of the Cvclorriiaplia. 



A discussion of the significance of these characters is outside the scope of the 

 present work. Bat the Stratiomyiidae have been taken first, both on account of 

 the usually accepted position of the family, and because the abundance and ac- 

 cessibility of the material makes possible a fuller investigation of the life-liistory 

 of one of this gi-oup, than is the case with the majority of the other families 

 studied . 



