Dolichopodidae. 13 



tubes, generally somewhat pointed. The abdominal segments have 

 each, generally except the first, a transverse girdle of short, flat spines 

 of unequal length. There are seven pairs of abdominal spiracles. 



The known larvæ live in the earth, in sand or in decaying wood; 

 they are no doubt all carnivorous, and this has been observed with 

 regard to the larvæ of Medeterus, which have been found feeding on 

 larvæ and pupæ of Tomicins. The pupæ are fomid on the same 

 piaces at the larvæ; they rest in a cocoon formed of particles of the 

 material they live in, earth, sand or particles of decaying wood, 

 The cocoon is on the inside clothed with a delicate film or web, and 

 it is somewhat solid; it seems also to be somewhat impenetrable, but 

 it has at one end a small, circular opening, through which the ends 

 of the spiracular tubes project. Sometimes (species of Medeterus) the 

 cocoon seems to be only formed of a web or of some silky substance. 

 — With regard to the developmental stages of Thrypticus, the larva 

 of which is described as phytophagous and peripneustic, see under 

 this genus. — The larvæ hibernate, and the transformation to pupa 

 and the development of the imago take place in spring and summer. 

 Some species have perhaps more than one brood in the year. 



Some species of Dolichopodids seem to be able to hibernate as 

 imagos, thus Drewsen has recorded (Krøyer's Tidsskr, IV, 1843, 349), 

 that lie found Hydrophorus nebulosus, hipiinctatus and balticus and 

 Campsicnemus scambus at the end of November in Bøllemosen (when 

 the author also mentions H. vindis this is certainly due to a wrong 

 determination, as this species is not known from Denmark); the temper- 

 ature had in the foregoing days been as low as -^ 8°, and there 

 was thick ice on the water. I have myself taken Camp. scambus 



on 20/12. 



The family of the Dolichopodidae is very characteristic, and the 

 species are easily known by the venation of the wings, especially the 

 confluent discai and second basal cell, and the generally present, cu- 

 rious convexity on the discai vein, as also by the nearly alvvays me- 

 tallic, more or less green colour. They are small or of medium size, 

 from one to about nine millim. They are also characterised by the 

 postocular bristles, the generally present great difference in the size of 

 the mouth parts in the two sexes, the hypopygium of the male with 

 the eighth segment and the opening lying on the left side; also the 

 antennæ are characteristic, and likewise the chætotaxy. The shape of 

 the antennæ, and the venation of the wings show, that they approach 

 to the cyclorrhaphous flies. Not only by their shape but also by 

 their behaviour they are rather characteristic, as at all events most 

 species sit in a curious, somewhat upright position, because they are 



