100 Phoridae. 



base. The sacks are somewhat pear-shaped, broadest below, erect, 

 and attenuated iipwards, the upper part is black; on the hinder side 

 each sack bears a patch of bristles and anteriorly, towards the lateral 

 margins of the fourth segment, there are likewise some bristles (figs, 

 40, 41). The sacks may be seen protriiding to a difTerent degree and 

 sometimes unsymmetrically, one protruding the other withdrawn. — 

 Wings with the apical part brown darkened, this browning is some- 

 times very distinct and rather distinctly bordered inwards, at other 

 times more effaced or nearly wanting; costa considerably thickened 

 in the middle, attenuating towards each end. 



I 



Fig. 42. Wing of Ch. thoracica ?. 



Length. The species varies much in size, the length varying in 

 all from 2 to 5,5 mm, the female is always the larger; for the male 

 the length is 2 — 3,5 mm for the female from fully 3 — 5,5 mm. 



Ch. thoracica is rather common in Denmark, Vesterfælled, Erme- 

 lund. Dyrehaven, Holte, Bogø south of Sealand, on Langeland at 

 Lohals, on Lolland at Lysemose and in Jutland at Ry, Grejsdal at 

 Vejle and Hejls south of Kolding; the dates are ^^/s — ^Vs, but bred 

 specimens emerged at the end of April. Pupæ were taken on Vester- 

 fælled on Vi and in Dyrehaven on ^^4, the latter developing on ^^4; 

 in both localities they were taken in moles' nests (Rosenberg). The 

 species occurs otherwise in low herbage, and I have also taken a 

 specimen on an umbellifer; but generally the species may be seen 

 in some numbers on tree-stems, as also often recorded; in this way I 

 have taken it at Lohals and Hejls in the middle of July, and it seems 

 that the copulation takes place liere, for I have taken it in copula 

 on the stems on ^7?; when occuring on the stems the females had 

 very often the above mentioned abdominal sacks more or less extended 

 so that it seems rather probable that these sacks have something 

 to do with the copulation. 



Geographical distribution: — Europe down into France, towards 

 the north to Lapland; also in North America. 



