1910 ENTOMOLOGICAL SOCIETY. 31 



panion and the most truly "^domestic" animal in the world. Wherever man has 

 gone the house-fly has followed in his steps, from the arctic circle to the burning 

 tropics it dances in constant attendance, the uninvited guest. And yet, in 

 spite of all tliis, notwithstanding the fact that no living creature paid him 

 so much attention, he did not trouble himself about it beyond a most cursory 

 enquiry into its habits and life. This is not infrequently the case in zoological 

 science; we write monographs of inordinate length on species of animals whose 

 chief recommendation is that they are rare, whereas on the other hand, those animals, 

 frequently of great interest and importance, that are waiting on the threshold of 

 our laboratories for inquiry are passed over. The house-fly is one of the greatest 

 examples of this. In 1790, Keller made an excellent study of the "Stubenfliege ;" he 

 studied the life-history and anatomy and anyone who has seen the beautiful 

 memoir which he wrote and the charming illustrations will be filled with admira- 

 tion and wonder that so much could have been done with the scientific apparatus 

 then at the investigator's disposal. Previously and subsequently to that, those 

 great naturalists, Reaumur, DeGeer and Bouche, all included a short description 

 of this insect and its habits in their classic works. Since that time the only investi- 

 gators who contributed really valuable information have been Packard and Howard, 

 who have studied the life-history and habits in the United States. There is no 

 need for me to call the attention of Canadian entomologists to the great importance 

 of Dr. Howard's work, the value of which lies in the fact that he, above all in- 

 vestigators, showed the people of the United States, and of other countries too, 

 the serious role which the house-fly plays in our national life. I need only 

 refer to the excellent work which is being done by the New York Merchants' 

 Association to combat this danger from flies — than which such an association could 

 do no work more worthy — as an illustration of the manner in which a corporation 

 has taken the warnings, has proved them beyond dispute for itself and is applying 

 the results of such knowledge as it has gained to the amelioration of public life. 



It has been my good fortune during the past few years to be able to add a little 

 to our knowledge of this insect by a detailed study of its anatomy of which we had 

 no previous account, and its life-history and habits. The result of that work has 

 now been finished, though like most investigations it is not complete and it is my 

 intention to-night to give you briefly and in a popular manner some of the results 

 of my woxk and of the work of others who have been studying the habits of 

 this insect. 



First of all, you must understand that several species of flies inhabit houses, 

 some of these are frequently mistaken for the true house-fly (Musca domestica). 

 This species is easily recognizable by having on the dorsal side of the thorax four 

 almost black longitudinal stripes on a dusty grey ground which in certain lights 

 has a golden shimmer ; the ground colour of the abdomen is a buff yellow and there 

 is a dark brown median dorsal stripe; the whole of the dorsal side of the abdomen, 

 however, is overspread with a reflecting grey which gives it a blotchy appearance. 

 The average size of this species is 6-7 mm., but unfavourable conditions in the 

 larval life tend to produce dwarf specimens of the adults. The occurrence of these 

 smaller specimens was no doubt partially responsible for the popular idea that they 

 were young house-flies and this in turn led to the mistake that many non-etomo- 

 logical people make in believing the other species of fly which occurs in houses, 

 namely, Homalomyia canicularis, to be a young M. domestica. This lesser house-fly 

 differs on examination very considerably from M. domestica. In the venation of 

 the wings the fourth longitudinal vein of the wing of H. canicularis goes straight to 

 the margin as in all the members of the group Antliomyidoe, whereas in M. domestica 



