24 Bulletin de la Société Entomologique d'Egypte 



vibrations. The large forceps is then extended directly 

 l)ackwards & the abdomen of the male beni ronnd 

 so that tbc hinder ends of the two bodies are bronghl 

 into opposition. The forceps then close nj)on Ihebod}^ 

 of the female, nnless they miss, which not infre- 

 qnently liappens, as the male fly is nnable to see 

 what he is doing. In snch a case the whole ma- 

 nanivre is repeated. The males are apparently unable 

 to distinguish which of their companions are females 

 as they very frequently attemi)t to copulate with one 

 another ». 



The eggs after being laid were kept at a tempe- 

 rature of about 15° C. to 17° C. & the young larvae 

 hatched out six to ten days after laying. The period is 

 jirobably shorter in summer tlian in winter, the time 

 when my observations were made. 



The young larva when hatched immedially makes 

 its way to one of tbe soft decaying tissues. Its cha- 

 racteristic habit is to carry its tail buoyed up at the 

 surface of the water by the lloating cup formed by 

 the radiating lilaments. 



If the water is mudi disturbed c^ the larva made 

 to sink to the bottom ü is nble to retain a Inibble of 

 air between the tail iilaments of suliicient size to 

 su|)port resj)irati()n until it can rise again to the surface. 



There are four larval stages, llie duration of each 

 gradually lengthening from about seven days for the 

 first stage to about three weeks for the last. The habits 

 and ap[)earance of tbe larvae aie simihir in all stages; 

 in every case they become very mucb darker and 

 more opaque [)revious to a moult. 



When the pupa appears it is white but it turns 



