G. S. Graham-Smith 
469 
Flies belonging to at least four species, C. erythrocephala, S. calcitrans, 
F. canicularis and M. domestica, seem to enter for various purposes. 
Blow-flies, especially C. erythrocephala, frequently come in attracted 
by the presence of food in order to deposit their eggs. They will 
penetrate to the darker corners of the rooms and into various recesses 
in their endeavours to find any suitable materials on which to lay eggs, 
but individual specimens seldom remain long indoors, and do not seem 
to seek shelter in rooms. 
Large numbers of Stomoxys calcitrans , often enter in the autumn 
months. Though these flies occasionally attack persons in the room, 
their main purpose seems to be to seek shelter, for they may often be 
seen settled on the walls and furniture in the evenings. 
The males of F. canicularis come into rooms in great numbers 
throughout the season. Unless it be for social intercourse, the reasons 
for this habit are not evident, since relatively few females enter and 
the males are little attracted to food. They spend the greater part of 
the day flying about, chasing and circling round one another near the 
ceihng, and in the evening settle high up on the walls and furniture. 
By catching daily all these flies in one room it was shown that varying 
numbers enter almost every day throughout their season. In other 
rooms, where they were left undisturbed, great numbers were never 
present, so it seems hkely that there is a daily immigration and emi¬ 
gration and that the individuals do not remain indoors very long. 
Numerical estimates of the prevalence of this species in rooms based 
on captures in traps, on fly papers etc., are not reliable, since these 
flies are little attracted to the baits. In 1915 they were twice as 
numerous as M. domestica in the dining room, but their presence was 
hardly noticeable. 
It has been stated that when the house-fly becomes common in 
certain rooms it displaces F. canicularis, causing the latter to seek upper 
rooms and others free from house-flies. No evidence in support of this 
view was obtained, for F. canicularis remained abundant throughout 
the season in the kitchen, even when house-flies were most numerous. 
Its habits are so unobtrusive that it is likely to escape notice when 
house-flies become a nuisance. 
Undoubtedly the females enter rooms in smaller numbers than the 
males. They are less easy to identify, and so no attempt was made to 
ascertain their numbers, only a few being identified from time to time, 
but many were doubtless included amongst the ‘ other Anthomyidae ’ in 
Table II. 
