210 [September, 



male abdomen shrivels somewhat. It may he mentioned that the eggs 

 appear to be laid in long strings ; some females were found dead with 

 strings of 20 — 30 bright yellow^ eggs protruding from the abdomen. 

 The male and female pupae can readily be distinguished l»y their size 

 and also liy the length of their wing cases ; these are nuich shorter 

 (relative to the length of the leg-cases) in the male than in the female. 



Although this is a remarkable instance of sexual dimorphism, 

 owing to the reduction of the wdngs occurring in the male and not the 

 female sex, it is not the only one on record in the genus Sciara. Lund- 

 beck describes a species (S. blformi'^) from Greenland, in wdiich the 

 male is smaller than the female and has the wings abbreviated, but in 

 8. biformis the neuration is not so degraded as in the present species. 

 Kieffer describes a more normal case of dimorphism in S. menibrani- 

 gera, in which the male has normal wings, and the female has them 

 rudimentary, without any distinct venation. In other genera of the 

 Sciaridse (Epidapris, Bradysia, Peyerimhoffia.) various forms of re- 

 duction of the wings occur. One of the most interesting cases is that 

 of Peyeriinhi)JJi.a (Epidapus) scahiei, Hopkins, in which the female is 

 destitute of wings and halteres, while there are two forms of the 

 male, one with abbreviated and the other with normal wings. 



I have with some reluctance come to the conclusion that our species 

 is undescribed. Both by Winnertz' monograph and G-rzegorzek's table 

 (Berl. ent. Zeitschr., 1884, p. 49) it would appear to lie nearest to S. vir- 

 gnUornm, Winn., but that species has lighter legs, and moreover its male, 

 which has been subsequently described by Strobl (Wien. ent. Zeit., 

 XIX, p. 9&), has normal wings. S. biformis, Liindb., differs in several 

 details of coloration ; the male has different venation, and the female 

 has hyaline wings. The present species belongs to Sciara in the 

 restricted sense: it has three- jointed palpi, face not produced, eyes 

 slightly hairy, simple claws and typical venation in the female. I 

 therefore describe the species as follows : — 



Sciara semialata, sp. nov. Body, ^ , lon;,'th 18-2 mm. ; 9 , 3-0-3-3 mm. ; 

 wing len<,'th, g , 1-i mm. ; 9 , -^'O "uii- Division II, A. 1. B. b of Winnertz. 



Whole insect black, except for the base of the lialteres, and (in life) the 

 sides and incisures of the abdomen, which are yellowish ; and the front femora 

 and coxae, which are dark brown. The thora.x is distinctly, but not con- 

 spicuoiisly, shining. The wings, especially in the female, ax-e smoky black, 

 darker towards the anterior margin ; in the male a little| shorter than the short, 

 thick abdomen ; in the female as long as the more elongated abdomen. Vena- 

 tion as in the figures : in the female R' ends very slightly but constantly before 

 the base of the fork of the media; the "cross-vein" may be exactly in the 



