714 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, VoL. KKVlll 
which succumbed to an epidemic in Sanger’s Circus. Di'. Livingstone, 
the explorer, subsequently sent home specimens from African ele- 
phants. Brauer's own account of how he reared the first known flics 
from larvte obtained from the dung of some newly arrived Indian 
elephants in the Imperial Austrian Menagerie at Schonbrunn is a 
delightful tale that may be recommended to all diptcrologists.* 
In this group of OEstrids there remains to be mentioned the genus 
Gyrostigma, which is parasitic on rhinoceroses. The larvae have been 
obtained from the stomachs of two species of Asiatic rhinoceros 
namely /?. sumatreiisis and R. lasiotis. They resemble in most 
characters the Gastrophili, or horse-bots, but are larger. Since both 
species of African rhinoceros are the hosts of allied OEstrid larvae it 
would be surprising if the rhinoceroses of the Indian peninsula were 
exempt from these parasites. Sportsmen who have an opportunity 
should examine the stomach walls of newly killed rhinoceroses and 
should detach the larvae, if they are found, without injuring them. 
They should be preserved in alcohol. 
Elephants, as is well known, are ancient types of mammal which 
have long existed on the earth. The evolution of mammalian host 
and insect parasite must have proceeded simultaneously during 
the long ages of the earth’s history. Cobboldia, the elephant para- 
site, is therefore of special interest. The imago is a synthetic type 
which unites the characters of almost all forms of genuine CEstrid 
flies. I’he origin of the elephant is lost in the obscurity of geological 
ages, whilst the horse and the rhinoceros are both more recently 
evolved types of mammal and allied to one another. It is also signi- 
ficant, when we appreciate the relationship of the hosts, that the 
parasites of the horse and the rhinoceros belonging to the CEstrid 
genera Gastrophihis and Gyrostigma respectively are closely related. 
The deduction which may be drawn from these facts is that the para- 
sitism of CEstrid flies on mammals is of ancient origin. Host and 
parasite have evolved into their present form side by side : and where 
the mammalian hosts are allied, the parasitic larvse, which live in 
their stomachs, will turn into more or less closely related flies. 
Cavicolcp. This group comprises some fifteen or twenty species 
of CEstrid flies, whose common characteristic is that the larvae live 
in the cavities within the skulls of a variety of mammals. Sheep, 
antdopes, goats, buffaloes, camels,deer, horses and the' African elephant 
and hippopotamus are the hosts of these remarkable parasites. 
In many cases only the larva has been obtained and the adult fly is 
still unknown. Six or seven species of the genus CEstrus are known, 
but the only recorded Indian species appears to be CEstrns ovis L. 
which has been known to man from ancient times. It is said to be 
• “ Beitrage zur Kenntniss aus<?ereuropaischer OEstrirlen ”, by Dr. F. Brauer 
(1896) Denks. Akad. Wiss. Wien, vol. 64 259. 
