Chilton. — On Dipterous Insects. 277 



Art. XXXIII. — Note on the Occurrence in New Zealand of 

 Dipterous Insects belonging to the Family Blepharocerid.se. 



By Charles Chilton, M.A., D.Sc, F.L.S., Professor of Biology, 



Canterbury College. 

 [Read before the Philosophical Institute of Canterbury, 6th December, 1905.} 



Plate XLVI. 



Some three years ago Mr. G. R. Marriner brought me some 

 peculiar insect-larvae that he had obtained from a mountain- 

 stream near Lake Coleridge. Afterwards, in February, 1903, 

 I collected similar larvae in a rocky stream at Akaroa. These 

 prove to belong to the Dipteran family Blepharoceridce, a family 

 that does not appear to have been hitherto recorded from New 

 Zealand ; and, though I have as yet been unable to collect the 

 adult insects or to rear them from the larvae, I have thought it 

 desirable to give a brief description of the larvae, with one or two 

 notes on the family taken from Dr. Sharp's volume in the " Cam- 

 bridge Natural History,"* in the hope that the attention of 

 entomologists may be thereby directed to these insects. 



The Blepharoceridce constitute a small and little - known 

 family of the Diptera, and are found in Europe (the Pyrenees, 

 Alps, and Harz Mountains), and in North and South America. 

 The adult insects resemble the Empidce, but have strongly iri- 

 descent wings, and they execute aerial dances after the manner 

 of midges. 



The larvo?. are very peculiar in appearance, and are aquatic, 

 living in rapid rocky streams, clinging firmly to the rocks by 

 means of suckers on the ventral surface. According to Dr. 

 Sharp, they live only a short time when taken out of the highly 

 aerated water in which they exist. 



The larvae that I have present a close resemblance to that 

 of Curupira torrentium, Fritz Miiller, from Brazil. They are 

 about 7 mm. long and 2*5 mm. broad ; dorsal surface moderately 

 convex, ventral surface flat. The larva consists of six divisions, 

 on the ventral surface of each of which is a rather large round 

 sucker, and each division except the last bears one pair of pro- 

 jecting side lobes; the last division bears two pairs, and shows 

 marks of being really composed of two divisions. The cephalo- 

 thorax — i.e., the first segment — is larger than either of the four 

 succeeding divisions, and is about the same size as the last ; the 

 mouth is situated on its ventral surface immediately in front 

 of the sucker. The short antenna of two joints, slender, free 



* " Insects." part ii, by David Sharp ("Cambridge Natural History"), 

 London, 1899, pp. 464-GG. 



