422 Annals Entomological Society of America [Vol. V, 
tion, but, as far as I could ascertain, no work has been done in 
this country on its mouthparts and internal anatomy. Four 
papers in England and one of minor importance in France, 
which apply to this genus, if not to this particular species, are 
included in the Bibliography. 
Facts relating to its life-history have been recorded by 
Packard and others, and Prof. James S. Hine of Ohio State 
University is at present working on this side of the subject. 
The writer made observations on its life-history in South 
Africa, and conducted feeding experiments in connection with 
the transmission of a Trypanosoma disease from Portuguese 
East Africa. When on this work it was noticed that very few 
Stomoxys calcitrans larvee could be obtained from old, heating 
manure, but that, as a rule, perfectly fresh horse dung was 
chosen for oviposition. Where this was collected into heaps 
with stable refuse, and generated heat, nearly all the larve 
found in it were of Musca domestica. In rooms where food was 
kept the majority of flies were of the latter species, Stomoxys 
calcitrans being most prevalent in such places on dull, cool 
days. Counts were made of flies caught in the windows of two 
rooms of the Government Experiment Station at Rosebank, 
near Cape Town in 1910. In room A, the laboratory, over 
40% of the flies caught in a week were Stomoxys calcitrans, 
while in room B, one of the living rooms, Musca domestica, 
comprised 93% of the flies caught, while Stomoxys calcitrans 
was rarely taken, representing less than 3% of the whole. The 
distance between the two rooms was approximately 35 feet. 
The three flies most common in houses, all of which have a 
very wide distribution, being almost universal, are Musca 
domestica, the House-Fly, Homalomyia_ canicularis, the 
Lesser House-Fly, and Stomoxys calcitrans, The Stable-Fly. 
The particulars given with the accompanying figures in Plate 
XXXIII will suffice for their identification in the various stages. 
Musca domestica Linn. The House-Fly. 
Egg: About 1 mm. long, elongate, cylindrical, oval, rather more 
pointed at the anterior end, dull chalky white in color. About 100 to 
150 eggs laid in a mass in crevices in house refuse or accumulations of 
horse manure. Eggs hatch under favorable conditions in 8 to 24 hours. 
Larva: 7 to 10 mm. long when full grown, greasy white in general 
color, except for the darker color of the contents of the alimentary 
tract. This larva can be distinguished from others by the shape and 
size of the plates which surround the posterior respiratory apertures. 
