DIPTERA. 
113 
flies preying on others, flies oviparous, and flies ovovi- 
viparous; among the lame 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 house-fly (. Musca domestica ), the flesh- 
fly (Sarcopliaga carnaria ), the blow-fly or blue¬ 
bottle {Musca vomitoria), the brilliantly-shining 
green-bottle {M. chlora ), the yellow dung-fly {Scato- 
phaga stercoraria) , are all well-known species of the 
family of Muscidse. Space is limited, so I must con¬ 
fine wdiat I have to say almost to the flies just enu¬ 
merated. 
The larvm 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 
extremity 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 the summer 
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.” 
I 
