22 THE BOOK OF THE FLY 



brooded, but some at least are double or treble-brooded 

 in the year; records are wanting about many, and 

 which, if any other than the common drone-fly, are 

 multi-brooded. Anyhow, none appears to breed in 

 Great Britain as rapidly as do the house-fly, the blue- 

 bottle, and other muscid flies. 



The larvae of Conops flavipes are parasitic in the* 

 body of the adult bumble-bee, and they pupate therein. 



The small family of the Stratiomyidcc contains a 

 few fairly common species called soldier-flies; these 

 are interesting as linking Orthorrhapha with Cyclor- 

 rhapha ; their larvae are some aquatic (the star-tailed 

 maggots), others terrestrial, and some have hard shell- 

 like skins; but they are not so curiously like a creeping 

 marine limpet as are those belonging to the genus 

 Microdon (of the Syrphidcv), which are rare and 

 wonderful dwellers in ants' nests. 



There is a curiously shaped race of parasitic flies 

 which cling to the host like a louse, called Hippoboscida: ; 

 these have more than the usual provision of claws to 

 their feet, both in the number (normally two) and size 

 of the claws. The forest or spider-fly attaches itself 

 to some part of the body out of reach of the horse's 

 tongue. The ked, tick, or sheep louse-fly has a similai 

 mode of life, and, after selecting its host, it becomes 

 wingless. These flies, strange to say, nurse and nourish 

 their larvae within the oviduct, and, when one might 

 think that they were laying their eggs, they are deposit- 

 ing pupae or larvae just ready to pupate. There are 

 some species of the family of the louse-flies which 

 infest birds. 



The true gad-flies of the family of Tabanida were, 



