78 FLIES. 
their usual activity ; and eight days after pairing the females lay their 
eggs on various substances, as damp spoiled provisions, decayed meat 
or broth, slices of melon, dead animals, also in dung-pits, and places 
where manure is stored, &c.; and Dr. Taschenberg also mentions the 
maggots as being found most especially in horse and fowl-dung.* 
John Curtis (in paper previously cited) writes as follows :— 
“The House Fly, Musca domestica, like most other insects, lays 
egos; . . . these are deposited in hot and moist dung-hills, and 
probably in putrefying vegetables, and refuse in gardens, muck-bins, 
and similar situations, and hatching into minute maggots of a dirty 
white and yellow colour, they feed until they arrive at the size of 
figure 2.” [This, in Curtis’s paper, represents a cylindrical legless 
maggot, about a third of an inch long, and rather more than a 
sixteenth in width at the thickest part, blunt at the tail extremity, 
and gradually tapering to the head end, as represented, much magni- 
fied, in my own figure 5, p. 76.] ‘‘ When fat and full fed, they lie 
dormant a few hours, during which time the skin hardens, and becomes 
of a chestnut or rusty brown colour. . . . In this quiescent state 
they remain from a few days to as many weeks, according to the 
temperature, many of them no doubt sleeping through the winter. 
Whilst in this state, the maggot is undergoing a wonderful transfor- 
mation within his own skin, which at last opens at one end by a little 
circular lid, and out creeps the House Fly, with its body and six legs 
as large as they are at any subsequent period of its life,—indeed, the 
abdomen is often larger, as it is filled with a fluid which is afterwards 
discharged.” A description is also given, unnecessary to enter on in 
detail here, of the method by which the two wings, which, when the 
fly comes out of its chrysalis case, are merely two little crumpled up 
objects placed one on each side of the body, are expanded until they 
gain the iridescent membranous transparent state in which we are 
best acquainted with them. } 
Referring to duration of the life of the fly in larval and pupal state, 
together with effects of low temperature in lengthening duration of 
these conditions, Mr. Edw. A. Butler gives the following remarks :— 
‘The larval life of the House Fly lasts about a week, during which 
time the maggot is said to change its skin twice, altering its form to 
some extent on each occasion. By the end of this time it is full grown, 
and passes into the pupa condition, which in about another week 
gives place to the perfect form. . . . They are very dependent on 
temperature, and unless there is sufficient warmth their development 
is delayed, and they become more or less dormant; hence all speci- 
mens that are in the larval or pupal condition at the approach of 
* «Praktische Insektenkunde,’ by Dr. E. L. Taschenberg, pt. iv. p. 104. 
+ ‘Gardeners’ Chronicle’; paper by John Curtis, previously referred to, 
