THE FLY-KILLING FUNGUS 41 



than those of the fly-larva or pupa. In the summer, 

 and in hot damp climates, the servants frequently 

 complain that they find dead flies glued to the window- 

 panes ; this is caused by a fungus disease. The bodies 

 of such dead flies can only be removed from the glass 

 with some trouble. It is caused by the fly becoming 

 infected with the spore of a fungus belonging to the 

 family Entomorphthorere. The spore multiplies into 

 long microscopic threads, which push their way into 

 the body of the fly and penetrate its tissues. The 

 threads produce more spores, and these again more 

 threads or hyphce until the body of the fly is completely 

 destroyed as by a canker. At the same time the kyphce 

 grow outwards and spread over the spot where the 

 diseased fly which has become sleepy and sluggish 

 happens to be, and thus the fly dies glued to its last 

 resting-place. At Port Said, during the hot weather, 

 the bodies of hundreds of flies destroyed by this disease 

 are found stuck over the windows of the abattoir and 

 the quarantine stables. This fungous affection of 

 flies is a most interesting and may be a most important 

 factor in fly-reduction ; many experiments have been 

 conducted and are being carried out now with a view 

 to discovering new information concerning it, for it 

 might conceivably be used to prevent flies ; that has 

 been suggested. 1 But even under the most favourable 

 circumstances the numbers of flies so destroyed, even 

 in hot climates, is small in proportion to the fly popu- 

 lation. Without doubt, fly-reduction at present rests 

 in destroying fly-larvae. 



There are mites which cling to flies ; but it is 



1 A Report on this parasite of house-flies (Emjtusca rtudusae) by Dr. Graham 

 Smith to the Local Government Board is promised in 1913. Dr. Morgan 

 and others have succeeded in cultivating this parasite artificially. 



4 



