G. S. Graham-Smitii 
447 
of wood, etc., without attempting to burrow into the earth. This fact 
in conjunction with observations on buried carcases mentioned later 
(p. 503) points to a tendency towards pupation within a very short 
distance of the surface or occasionally under shelter on the surface of 
the ground. That exposed pupae are not injured by low temperatures 
is evident from the emergence of a very large number of flies from 
pupae in the “tins,” and outdoor cages in the spring months of 1915 
and 1916 (see p. 543). The minimum temperatures recorded on the 
grass during the two winters were 17° F. and 12° F. In many cases 
the pupae lay on the top of the earth in the “ tins.” 
These observations show that most of the common species of flies 
pass the winter as pupae, or less commonly as larvae, in the earth. 
These larvae pupate as the spring approaches, and flies emerge from 
them a few days later than they do from winter pupae. 
The species definitely proved by experiments extending from 1912 
to 1916 to be capable of passing the winter in this manner are: 
Calliphora erythrocephala 
Fannia manicata* 
Fannia canicularis* 
Fannia scalaris* 
Anthomvia radicum* 
Tephrochlamys canescens 
Blepharoptera serrata* 
Scatophaga stercoraria 
Dryomyza flaveola* 
Calliphora vomitoria 
Nemopoda cylindrica* 
Piophila vulgaris* 
Hydrotaea dentipes 
Sarcophaga melanura 
Sarcophaga carnaria 
Stomoxys calcitrans 
Mydaea lucorum 
Lucilia caesar 
Lucilia sericata 
Phaonia erratica 
Muscina stabulans 
Muscina pabulorum 
Ophyra leucostoma 
Polietes lardaria 
Observations during the winter of 1915-16 indicate, however, that 
a few individuals, insignificant in number compared with those passing 
the winter as pupae, may hibernate in the adult condition. In the 
perpetuation of the species these are probably of little account. Daily 
observations in the blow-fly cage outside showed that throughout the 
winter a few flies, which emerged from pupae from time to time, were 
present there. In January, 1916, for example flies emerged on the 
10th, 18th, 21st, 26th, 28th, 29th, and 30th. 
Some of these flies lived for several weeks, and survived heavy rain, 
snow, frost, cold winds and gales, and exhibited the most astonishing 
powers of resistance (see p. 465). 
1 This list is arranged according to the order in which the species have been observed 
to emerge, but the dates of emergence are not given since they depend on the weather 
conditions and vary in different years (see p. 452). 
