58 



AUSTRALIAN' DIXID.Y.. [Dipt.] 



By A. L. ToNNOiR, 



Research Student in Diptera at the Cawthron Institute, 



Nelson, N.Z. 



(Comniunicatt'd by C'livc Lord.) 



(Read Gth August. 1923.) 



INTRODUCTION. 



Previously nothing was known of the representatives of 

 this family in Australia except a record of Skuse <i) saying 

 that he knew three species belonfiinj? to the genus Dixa in 

 New South Wales; they remained, however, undescribed, and 

 I have been unable to find the specimens in his collection, 

 preserved pro parte in the Australian Museum in Sydney 

 and pro parte in the Macleay Museum in Sydney University. 



During a short stay in New South Wales and Victoria 

 and one summer spent in Tasmania, I found five species of 

 Dixa, and recently Mr. A. J. Nicholson discovered another in 

 New South Wales, which he kindly gave me for study, for 

 which loan I am much obliged to him. 



The.se Australian species indubitably belong to the genus 

 Dixa, as they differ very little fiom the forms of the rest of 

 the world; like them, they are differentiated from each 

 other by mere details of colouration, relative length of 

 antenna\ peculiarities of venation such as the position of 

 r-vi and relative length of fork of J,'^ , .< and chiefly by the 

 structure of the hypopygium. 



Their larvjc of which three types have been secured, 

 differ also very little from the European forms. Like them, 

 some have the peculiar crown of hair on the dorsum of the 

 abdominal segments 2-7, and some present this d :)rsum com- 

 pletely smooth; they arc provided also with the pair of 

 pseudopods on the two first abdominal segments, the arma- 

 ture of hooks on the G-8 segment; the mouth-parts and 

 spiracular armature present only minute differential char- 

 acters in their structures. 



(1). Austral. Aaa. Adv. Sci., Melbourne, Vol. II.. 1800, p. 680. 



