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DIPTERA (TWO-WINGED ELIES). 
The larvae of the Bot-flies and Gad- or Warble-flies {(Estrides) 
are mammal parasites. They are white and grublike in shape, 
and live in the nostrils, frontal sinuses, pharynx, stomach and 
intestine, or beneath the skin. The majority are parasitic upon 
Ungulates; but the larvae belonging to the American genus 
Cutiterebra are found beneath the skin of Rodents. It may be 
noted that larvae belonging to this family rarely survive forcible 
removal from the host. Pupation invariably takes place upon or in 
the ground, under stones, etc.; therefore, in order to breed out the 
perfect insects, an attempt should be made to obtain the larvae as 
they leave the host in order to pupate, or the pupae themselves 
should be sought for in the situations indicated, in places frequented 
by the animals. In the case of domestic or other animals, kept in 
captivity and infested by these parasites, the pupae or larvae about to 
pupate may sometimes be obtained by searching in the stalls or 
sheds at the proper season. According to Brauer the majority of 
(Estrid larvae leave their hosts in the early hours of the morning. 
The larvae of the Muscidce {sens'd latiore) are 
well known as maggots, and are to be found in 
decaying matter of all kinds, and even in fes¬ 
tering sores and wounds on living animals; 
those of the sub-family Tachinmce are parasitic 
in other insects—the majority in caterpillars. 
FABRIC!A FEROX. 
The habits of the larvae belonging to the families constituting the 
Acalypterate Muscidce are too diversified to be dealt with in detail. 
Some fire to be found in ordure; others attack the stems of grasses 
;md cereals; while the larvae of others again (e.g. Trypetidce) live in 
fruits, in seed-heads, in galls on the stems, or mine in the leaves of 
various plants. 
How to Preserve Larvae. 
Specimens of larvae will always be valuable, whenever it is 
possible to breed out some of them so as to determine the fly to 
which they belong. Unless, however, the perfect insect is known, it 
is rarely possible to do more than to determine the family or genus 
