DIPTERA. 113 



flies preying on others, flies oviparous, and flies ovovi- 

 viparous; among thelarviie are found some terrestial and 

 some aquatic, carrion-feeders, vegetarians, and wine- 

 bibbers ; parasites in the nests, and parasites in the 

 bodies of other insects ; gall-makers and leaf-miners. 

 The common liouse-fly (Musca domestica), the flesh- 

 fly (Sarcophaga carnarla), the blow-fly or blue- 

 bottle {Musca vomitoria), the brilliantly -shining 

 green-bottle (J/, cklora), the yellow dung-fly {Scato- 

 phaga stercoraria), are all well-known species of the 

 family of Muscidae. Space is limited, so I must con- 

 fine what I have to say almost to the flies just enu- 

 merated. 



The larvai of the House-fly are found in dung in 

 stables, in the fields, and by the road-sides in great 

 abundance ; they are small footless grubs, slightly at- 

 tenuated in front with a small head ; the mouth is 

 furnished with two retractile hooks, and at the posterior 

 exti'emity there is a pair of stigmata for respiratory 

 purposes. The pupa is enclosed within the skin of the 

 larva. It is curious to notice the first appearance of 

 the common domestic fly in public ; his whole skin, on 

 emerging from the pupa case, is soft and white ; the 

 wings are a thick opaque and wrinkled mass. After a 

 few hours' exposure to the air and warm sun the crea- 

 ture is transformed into that " intrusive, buzzing, pilfer 

 ing, boozing, tickling varlet,"so annoying in thesummei 

 months, whose irritating behaviour is not stopped till 

 the cold weather arrives : — 



" When his two pretty pinions of blue dusky gauze 

 Are glued to his sides by the frost." 



