MUSCA DOMESTICA 333 



For practical purposes the genus Musca may be divided into two 

 groups as follows : 



GROUP 1. The non-blood-sucking species, including all the house 



flies. 

 GROUP 2. The non-biting, blood-sucking species, including those 



wild forms closely resembling Musca domesticct. 



GROUP 1. THE NON-BLOOD-SUCKING SPECIES OF MUSCA 



To this group belong those species of Musca which are domestic in- 

 sects, living on all kinds of human and animal food, and on filth and 

 garbage of every description. They come into houses and settle on food, 

 cooked or uncooked, and on being driven away seek nourishment either 

 from horse manure, COW T dung or human excrement. They worry man 

 especially when he has sores or foul discharges, and the reader if he has 

 been in an Indian or African bazaar will recall the swarms of flies 

 buzzing round some food or the sore eyes of a child. These insects 

 are a constant source of danger to man, for they not only infect his 

 person with bacteria, but certainly contaminate his food. 



The true Musca domestica is found in most parts of the world. 

 It is said to occur in North India, but is not to be found in South 

 India. There is, however, no accurate information on this point, and 

 this is perhaps mainly due to the fact that there are no simple complete 

 descriptions of the group available for general use ; the result is that 

 most observers who have studied the species of Musca in their relations 

 to. disease germs have simply spoken of them as house flies ; to the 

 zoologist this term only refers to the species Musca domestica, L. 

 It is of some importance to know exactly which species is being dealt 

 with, as those which only breed in cow dung or the refuse around 

 slaughter houses are not of so much importance as those which breed in 

 human excrement. 



The following short descriptions of Musca doinestica and some of 

 its allies will help the worker to identify his species. 



Musca domestica, L. Male- Thorax, ground colour yellowish grey 

 to dark grey, with four equally broad black longitudinal stripes ; shoul- 

 ders slate grey ; scutellum dark grey with an indistinct broad central 

 band. First to third segments of abdomen orange yellow with a median 

 black longitudinal stripe, broadest on the third segment. Fourth seg- 

 ment with an indistinct diffuse olive grey patch about the centre, sides 

 lemon yellow. In certain lights a shimmering white band is seen on 



