168 
Fannia caniciilaris etc. 
is not unlikely that larvae, which have developed very late in the 
season, pass the v/inter in the pupal state, as is the case in certain other 
species of Anthomyid flies. The adult fly emei’ges by pushing off the 
anterior segments of the pupal case. 
F. scalaris Fab. 
{The Latrine Fly.) 
This species which, on account of its most common breeding habits, 
may be called the Latrine Fly, is very common both in European 
countries and in North America. Owing to its general similarity, it 
is often confused with the Lesser House-fly, F. canicularis, but the chief 
differences have already been indicated. 
The descrip)tion of the adult of F. scalaris is as follows: 
Male. The frontal triangle on the head is black and is continued 
as a thin line to the vertex, being bordered on each side by a silvery 
white stripe. The antennae and palps are black. The thorax and 
scutellum are black and somewhat polished; the humeri are light- 
coloured. The abdomen is black, overspread with bluish grey and has 
a darker median stripe from which dark transverse bands arise forming 
by their junction with the median stripe black triangular markings. 
The legs are black and the middle femur is swollen ventrally, bearing 
on its broader side a group of brush-like bristles as will be seen from 
Fig. 3. The middle tibia is provided, as shown, with a distinct tubercle 
near the distal end. 
Female. The colouring is more distinctly grey with a faint 
longitudinal striping on the thorax ; the transverse markings on the 
abdomen are also indistinct. The head is grey with a wide frons. 
F. scalaris is slightly larger than F. canicularis, measuring up to 
6 mm. in length. 
The habits of this species are somewhat similar to those of F. cani¬ 
cularis but it prefers excrementous matter as a nidus for the eggs and 
is very commonly found breeding in human excrement. It has been 
recorded breeding in human excrement by Schiner, Taschenberg, 
Howard and New’stead and I have also bred it from this material in 
England and Canada, both in privies where the excrement w^as found in 
a semi-liquid condition and on rubbish tips or dumps where it w'as mixed 
with ashes or clinker. Swammerdam figured what would ajDpear to be 
the larva of this species as breeding in human excrement. Taschenberg 
