28 THE BOOK OF THE FLY 



markable attractiveness of the odour of humanity to the 

 common house-fly, and from the fact of the maggots 

 possessing well developed tenter-hooks on their heads 

 (somewhat like those which the bot-fly maggots use 

 for internal attachment), it is just as likely, nay more 

 likely, that this species (as the writer stated for the 

 information of the authorities of Westminster Hospital 

 nearly fifty years ago) is more than any other capable 

 of adopting such a life-cycle existence ; these maggots 

 would mature after five or six days feeding and then 

 emerge. If there were a veritable " QLstrus hominis," 

 however rare, the hairy and peculiar female would be 

 conspicuously observable, a persistent hoverer about 

 the person of her victim until she had attached eggs 

 to his body, from which the maggots would not emerge 

 until after nine months. Most of the tropical flies, 

 which are said to similarly attack humanity, may be 

 rather compared to the green-bottle flies which infest 

 sheep, but the latest medical records and reports profess 

 to identify ten or twelve species of very different genera 

 as having myiasic capabilities. 



The family of (Estrida has been fitly divided into 

 three sections, namely, the Gastrophilincv (the larvae 

 living in the gullet, the stomach, or the intestines), the 

 Hypoder mince (worble-flies), and the (Estrincc (nasal 

 or nostril flies) ; all the species are hairy or furry, and 

 the gravid females fly slowly with loud buzzing, in a 

 characteristic attitude peculiar by the bending down- 

 wards of abdomen and tail, with a much extruded 

 ovipositor. 



The sheep's nostril-fly, (Estrus ovis, has a chequered 

 abdomen and is less hairy than others ; it is the type of 



