(2) 



396 0. GORDON HEWITT. 



include an account of the anatomy of the larva, its develop- 

 ment and the breeding habits of the fly ; the series will be 

 concluded with an account of the bionomics of the fly with 

 special reference to its relations with man. 



The term " House-fly " to the zoologist refers only to one 

 insect Musca domestica of Linnaeus, but to the popular 

 mind it includes insects, not different species only, but differ- 

 ent families of Diptera. The Root Maggot fly (PL 22, fig. 2), 

 Anthomyia radicum, L., sometimes occurs commonly in 

 houses. Homalomyia canicularis, L. (fig. 3), often 

 called the Small House-fly, is a very common inhabitant of 

 houses. The latter species is smaller than M. domestica, 

 and on this account they are frequently supposed to be young 

 specimens of the latter species by persons who are ignorant 

 of the fact that growth takes place during the larval stage 

 and not after the exclusion of the imago. Stomoxys 

 calcitrans, L. (fig. 4), is found in houses, especially in the 

 autumn. It is frequently mistaken for M. domestica, and 

 as it is one of the blood-sucking species (See Austen, 

 1906), the pernicious habit is attributed to the harmless 

 M. domestica either on account of the supposed ill-nature 

 of the latter or the influence of some change in the 

 weather. 1 



In addition to these, other species of flies occur in houses 

 but these will be considered in a later part. Reference has 

 been made here to the various species inhabiting houses to 

 show that the term " House-fly" as ordinarily used is rather 

 an inclusive one. 



The House-fly has received some attention from naturalists 

 in all ages. Reaumur (1738), De Geer (1752-78) and Bouche 

 (1834) have all included a short account of this insect in their 

 classical memoirs. They do not contribute much to our 

 knowledge of the anatomy and development of the fly. The 



1 Stomoxys calcitrans can be readily distinguished from M. domes- 

 tica by the awl-like proboscis which projects forwards from beneath the head. 

 It has a more robust general appearance, a dark spotted abdomen, and its 

 flight is more steady. 



