8TRATIOMYIDAE. 17 



Two of the species of RACHICERUS cannot be well placed in this 

 genus without a modification of its characters. 



Observation. I have to mention here the genus BOLBOMYIA, 

 which I established on two fossil species found in Prussian amber. 

 When I published in 1850 my observations on the Dipterological 

 Fauna of amber, I thought it would be best placed among the Xy- 

 lophagida. But I perceive from a N. A. specimen belonging to 

 Bolbomyia that its claim to that place is more than doubtful, and 

 at the same time that it is quite as difficult to assign it a fit place 

 elsewhere. 



FAM. XII. STRATIOMYIDAE. 



Char act. Three basal cells much prolonged ; veins of the two main trunks 

 very crowded anteriorly ; both intercalary veins usually existing ; 

 costal vein reaching only to the middle of the wing. Third joint 

 of the antennae annulated, sometimes divided into several portions. 

 Tibiae without spurs ; empodium much developed, pulvilliform. 



This family, rich in various forms, may be divided into five 

 sharply circumscribed sections. The first is that of the BERIDINA, 

 easily distinguished by the abdomen not showing five segments, 

 as in the other sections, but seven, a difference caused only by the 

 smallness of the two last segments and their concealed situation in 

 the other sections. The Beridina have often been placed in the 

 family of Xylophagida, but figure more naturally among the Stra- 

 tiomyidee. The genera belonging to then! are : METOPONIA Macq. 

 {= Inopus Walk.), BERIS Latr., ACTINA Meig., EXODONTHA 

 Rond., ACANTHOMYIA&A., DIPHYSA Macq. , CAMPEPROSOPA Macq., 

 perhaps also EXOCHOSTOMA Macq.; also the genus CHIROMYZA 

 Wied., which does not differ from Xenomorpha Macq., may be re- 

 ferred to them. The second section is that of SARGINA, rather 

 agreeing in the form of the body with the Beridina, and even 

 with the Hermetina, but differing from the former by the abdomen 

 consisting apparently of five segments, and from the latter by the 

 eyes of the males being much more approximated than those of 

 the females. As genera of this section may be mentioned CACOSIS 

 Walk., ACROCH^ETA Wied., EU.DMETA Wied., ANALCOCERUS Loew, 

 SALDUBA Walk., TOXOCERA Macq., HOPLISTES Macq., RAPHIOCERA 

 JH/acg-.jBASENTiDEMA Macq., DiCRANOPHORA Macq., CHRYSOCHLORA 

 Macq., PTECTICUS Loew, MEROSARGUS Loew, PEDICELLA Big., 

 2 



