DURHAM DIPTERA. 105 



XVIII. 



169. Laphria, Mg. 



24 (25). Thorax black without a trace of lighter dusting on 



the shoulder or light reflections on the pleura?. 



(952. flava, L.) 



25 (24). Thorax black with grey dusted shoulders, pleurae 



spotted. (953- marginata, L.) 



26 (23). Third antennal joint with a terminal bristle (III. 19). 



27 (28). Large bright coloured species, varying from brown to 



gold. 170. Asilus, L. (954. crabroniformis, L.) 



28 (27). Grey, greyish yellow, or black species, not bright 



coloured. 



29 (30). Dorsum covered in front as well as behind with 



equally long bristly hairs. 



179. Dysmachus, Lw. (964. trigonus, Mg.) 

 80 (29). Front of the dorsum quite bare, or with much shorter 

 hairs than behind. 



31 (36). The eighth abdominal segment of the male produced 



in a point beneath, or furnished with a pointed 

 tuft of hair. Ovipositor always compressed at the 

 sides. 



32 (33). Legs all black. 



178. Eutolmus, Lw. (963. rufibarbis, Mg.) 



83 (32). Legs partly orange. 



177- Machimus, Lw. 



84 (35). The point on the under side of the eighth abdominal 



segment of the male divided at the end so as to 

 appear two-horned. Dark grey species. Hind 

 scutellar bristles black. (961. atricafiillus, Fin.) 



35 (34). The point under the eighth abdominal segment in 



the male not divided. Yellowish grey species. 



Hind scutellar bristles yellow. 



(962. rusticus, Mg.) 



36 (31). The eighth abdominal segment in the male not 



pointed beneath, at most with short hairs which 

 do not appear pointed. 



