\/' 



PSYCHE 



VOL. XXVIII FEBRUARY. 1921 No. I 



ATHEBIX BRAUNSI NOV. SP., A SOUTH AFRICAN 



LEPTID WITH GREGARIOUS HABITS (DIPTERA). 



By J. Bequaert, 



American Museum of Natural History, New York City. 



The genus Atherix is unique among the Leptidse on account of 

 the remarkable, gregarious habits exhibited by the adults of cer- 

 tain, if not all, of its members. These have l)een repeatedly de- 

 scribed for the Iliis fly, Atherix ibis (Fabricius), the commonest 

 of the European species. "The female of this fly," says Walker,^ 

 "is gregarious, and attaches its eggs in large clusters to boughs 

 hanging over streams, and there remains, and shortly dies. The 

 cluster is generally pear-shaped, and sometimes contains many 

 thousands of dead flies, and continually receives accessions by new 

 comers settling upon it. When the larva is hatched it falls into 

 the water, its futiu'e residence ; it has a forked tail about one-third 

 the length of the body, and has the power of raising itself in the 

 water by an incessant undulating motion in a vertical plane."^ 



I am not aware that similar observations have been made on 

 other European species, nor that the metamorphoses of any of these 

 have ever been elucidated. In North America, however, A. varie- 

 gata Walker, a close ally of A. ibis, also oviposits in dense clusters. 



^ Walker, F. Insecta Britannica. Diptera. Vol. 1, 1851, p. 70. 



2 D. Sharp (The Cambridg-e Natural History, In.sects, Vol. 2, 1909, p. 480. 

 fig. 227) has given a good figure of the egg and fly clusters of A. ibis. Of the 

 many naturalists who have observed the habits of this fly I may mention 

 the following: 



Egger, J. Verb. Zool. Bot. Ges. Wien, 4, 1854, p. 7. 



Schiner, J. R. Fauna Austriaca, Die Fliegen. Vol. 1, 1862, pp. 177-178. 



Chapman, A. Masses of Diptera collected on twigs of alder. Ent. Mo. 

 Mag., 3, 1866, pp. 94-95. 



Tournie'-, H. and Preudhomme de Borre, A. Ann. Soc. Ent. Belglque, 17. 

 1874, C. R., pp. Ixxxix-xci. 



P^rez, J. Actes Soc. Linn. Bordeaux, 32, 1878, C. R., p. xliii. 



Billups. T. R. Note upon Atherix Ibis, Fabricius. Entomologist, 22, 1889, 

 pp. 193-194, PI. 7; also mentions and figures parasitic Hymenoptera obtained 

 from the egg cluster; W. H. Ashmead (p. 290) and F. W. Frohawk (pp. 

 290-291) comment further on these parasites. 



Giard, A. Note sur la larve de I' Atherix ibis Fabr. Bull. Soc. Ent. France, 

 1902, pp. 220-222. 



