Te INSECTS AFFECTING DOMESTIC ANIMALS. 
Family CHSTRIED Ai. 
(Bot-flies, Breeze Flies.) 
The bot-flies form a distinct family, easily recognized in larval or adult 
stages. The adults are heavy-bodied insects, generally rather hairy, 
and characterized by the small eyes standing at the sides of the head, 
the small antennz sunken into deep pits on the front of the head and 
by the rudimentary mouth parts. 
The larve are thick, fleshy grubs living parasitically in various por- 
tions of the bodies of mammals, the alimentary canal, the subcutaneous 
tissue, nasal passages, etc. The tracheal openings are located at the 
posterior extremity and protected by horny plates. 
Frequently the segments are provided with rows of spines which 
serve to assist the animal in locomotion. The pupa stage is passed in 
the ground, the parasite leaving its host and entering the ground for 
this purpose upon attaining its full larval growth. 
Irom the manifest economic importance of the different species and 
the great interest attaching to the habits of the species, which depart 
widely from even the most nearly related forms, they have been the 
subjects of investigation from the earliest periods of scientific work. 
The habits in general of the more common species were known more 
than a century ago and stated in the works of Linneus, DeGeer, 
Reaumur, and others, while the later studies, early in the present cen- 
tury, by Clark and afterwards by Joly, Brauer, and others, have cleared 
up most of the essential points in their life history. 
For the most part, these must be stated in detail for each species, 
since the habits are very different among the different species, aud par- 
ticularly so in the different genera. 
In all cases the eggs are deposited on the animal to be infested, 
either where the larve will gain access to the proper part, or in direct 
contact with the parts to be invaded. 
In one case, at least—the sheep bot-fly—the eggs may have NEE 
hatched and the free larve be deposited by the female. 
Studies of the young larva have been attended with some difficulty, 
though in the later stages they are well known and were accurately 
described at an early day. The full life of the larva has been a sub- 
ject of study by Joly and especially by Brauer, who presents in his 
‘¢ Monographie der Oestriden” a very careful discussion of the subject. 
A translation of this part has been published by Mr. Bb. Pickmann 
Mann (Psyche, Vol. IV, pp. 305-310), and the following extracts from 
this translation will be of such service in gaining a full understanding 
of the early life of the bot-flies in general that it seems desirable to 
include them: 
The larve of the stride, although in many cases quite peculiarly shaped, are so 
nearly related to the larve of the rest of the Muscidie-calyptra that it has not yet 
been possible to discover for them a constant distinguishing character founded upon 
their structure. The reason of this lies in part in the estrid larvee themselves, since 
