(ESTKID.'E. 385 



important recent contributions to a knowledge of the life-cycle, 

 but these do not seem to have been as yet gathered into any one 

 work. The lit'e-histories are very varied and sometimes highly 

 complicated. The larvae live either in the nostrils, throat or 

 stomach, or under the skin of the back of mammals, frequently of 

 ungulates and pachyderms, leaving the host wlien full grown to 

 pupate in the ground. The flies of those species that pass the 

 larval state in the stomach of Gastrophilus, etc. lay their eggs on 

 the h'.iirs of their hosts, usually on the knees, fetlocks or 

 shoulders, whence they are licked off by the animal, thus passing 

 into the body. Tiie young larvae affix themselves by hooks near 

 the head to the walls of the stomach, feeding probably not on the 

 tissues but on the secretions caused by the irritation due to 

 their presence. When fully grown they pass out with the dung. 

 The sheep bot-fly (CEstrits) is said to be viviparous: it places its 

 young larva) just inside the nostrils of the animal, and the sub- 

 sequent larval development occurs in the frontal sinuses. Cepha- 

 lomyia lives in the nostrils of the camel. Of the forms that 

 cause tumours under the skin the best known is ll>f/>0(lenna. It 

 forms tumours or warbles on the backs of cattle. The eggs are 

 laid on the legs or, more rarely, on the flanks, and the larvie 

 migrate by way of the gullet and diaphragm, or sometimes via the 

 neural canal, to the tissues beneath the skin of tlie back. When 

 nearly full grown they can easily be picked out of the warbles by 

 hand. The imago appears for only a brief period. A new 

 species of tliis genus, H, crossii, occurs in India. Ifypoderma 

 occasionally attacks man, and cases of human parasitism have been 

 recorded in Cephenomtjia and Gastrophilus. The most frequent 

 human parasite in the family is the Xeotropical Dernintohia, wliich 

 also attacks dogs and other carnivores, ungulates and rodents ; 

 in this genus the eggs are attached by the parent fly to the 

 bodies of mosquitos {Janthinosonia), or possibly also of certain 

 AxTHYMTiiD.E which attack vertebrates, and so are carried to the 

 hosts in whose bodies the larvae are to undergo their develoiiment. 

 Cuterehra, also an American genus, forms warblns under the skin 

 of mice aiul other rodents. The larvje of (Estrid;e have transverse 

 rows of horny hooks or bristles on their bodies. They also 

 possess month-hooks, and those forms which live in the stomach 

 of the host attach themselves to the stomach-wall by means of 

 these mouth-hooks, and cannot be dislodged even by the passage 

 of food or by medicinal purges. In temperate climates the winter 

 is passt^d, at least in some species, in the pupal stage. 



Notes on (EsTRn)/"E in India are given in ' Indian Insect LifV,' 

 pp. 651-1 (1901J). also bv Col. J. W. Yerburv, Journ. Bombav 

 Nat. Hist. Soc. xiii, pp. 683-0 (1901), and by'Col. C. (>. Nurse, 

 op. clt. liv, p. OOU (1902)*. Col. Yerbury has also drawn attention 



* Secnrrnin Ih'Idvv. p. 391. 



2c 



