82 
Hibernation of Flies 
The most numerous and troublesome fly was M. corvina. They might be 
present in hundreds on one day and have disappeared on the next. L. septem- 
notata occurred mainly in certain rooms, the outer walls of which were covered 
with ivy. Rooms infested with large numbers of one of these species seldom 
contained many of the other. 
Mr J. Waterston, who examined the chalcids, writes that “there is no 
doubt that the bulk are Stenomalus muscarum. The dark specimen is a 
rather undersized example of Pteromalus deplanatus Nees (1834).” Mr Grim- 
shaw very kindly identified the “small flies” as L. septemnotata Ztt. 
On examining an unoccupied house near Cambridge on March 5, 1918, 
hundreds of living and dead specimens of P. rudis were found in several 
rooms facing west. 
