Empididae. 5 



long bristles or hairs; on the ventral side there are only hairs. There 

 are prothoracic and seven pairs of abdominal spiracles. 



The larvæ live in the earth, below leaves on the ground in woods 

 or sonietimes in decaying wood; the larva of Hemerodroinia 2)recatona 

 was found in the mud in a streamlet. They are certainly carnivorous 

 as has been observed in some single cases. The larvæ hibernate, 

 and the transformation to pupa and final development takes place in 

 spring or summer. The species of Drapetis however seem to hibernate 

 or at all events to be able to hibernate as imagos (see under this genus). 



The family of Empididae is a large one including many genera 

 and species of somewhat varied aspect. They are medium sized 

 to very small flies, from about one to twelve or fourteen millimetres. 

 The colours are dark, grey or yellow^ish; some few tropical forms are 

 metallic. They are generally characterised by their somewhat small, 

 more or less globular head and the as a rule somewhat slender shape. 

 From the Asilidae they may be distinguished by the not excavated 

 vertex, smaller head always without epistomal beard, and by differ- 

 ences in the wing-venation , especially the short, sometimes wanting 

 anal cell. The species of Clinocera may show great resemblance to 

 some of the Dolichopodids e. g. the genus Hydrophorus, but may be 

 known by the always separated discai and second basal cell. Some 

 of the Tachydromiinae e. g. Chersodromia show some resemblance to 

 small Anthomyids or Borborids. A good character for the family is 

 also the incision about in the middle of the inner eye-margin; this 

 incision may be small but is always perceptible. The Empids are all 

 rapacious; many [direct observations have been recorded, and this 

 way of feeding is also indicated by their strong mouth and not rarely 

 raptorial legs. The prey observed for the single species will be noted 

 in the following. Some species are however also often seen on flowers, 

 probably also here sucking juices, The Empids occur especially in 

 woody more or less humid regions and also in mountainous districts; 

 in dry localities they are more rare in contrast to the Asilids. Some 

 are found on sandy horders of water. They seem especially to be a 

 boreal group, yet many species are in quite recent time recorded from 

 the mountainous districts in South America. 



Some species of Empids, especially of the genera RhampJiomyia, 

 Empis and Hilara are seen dancing or swarming in the air above 

 water and also elsewhere; this dancing takes place in connection 

 with the copulation. It seems to be sometimes the males but also 

 sometimes the females which perform the dancing, and at other times 

 also both sexes. The copulation takes then place in the air and is con- 

 nected with some interesting phenomena. With regard to many species 



