176 OUR HOUSEHOLD INSECTS 



calcitmns, the " sharp-mouthed stinger." If seen by it- 

 self, it would probably be mistaken for a house fly, unless 

 the extraordinary nature of the proboscis were noticed ; 

 but when the two insects are placed side by side, many 

 other differences become apparent, at least to the trained 

 eye. Stomoxys is not only smaller than M. domestica, 

 but it carries its wings wider apart when not flying, and 

 is more thickly covered with a greyish tomentum ; its 

 eyes, moreover, are not so red. But the strongest point 

 of difference lies in the proboscis, and in the disagree- 

 able habits of which that is the surest indication. 

 These three flies constitute the majority of what in 

 houses are commonly regarded as house flies, or are 

 simply called flies. 



But, besides these, there is the far larger bluebottle, 

 blow-fly, or meat-fly; this is usually one or other of 

 two closely allied species, Callipliora vomitoria and C. 

 erythrocephala. A bluebottle is easily recognisable by 

 its much larger size, its proportionally broader body, of 

 a shiny blue or violet colour, and the loud buzzing with 

 which it heralds its approach. Like its companions, it 

 is red-eyed, but its face is not silvery, only a narrow 

 margin of silver being visible behind each eye, while all 

 the lower parts of the face are more or less of a pale 

 reddish-yellow ; it is also more hairy than the other 

 species. When in good condition, it may be seen to 

 possess a tomentum like the others ; and this, in certain 

 lights, imparts a curious appearance to the steely blue 

 of the skin, reminding one of the lustre of shot silk. 

 These flies are, in the house, the chief assailants of cold 

 meat, of which they not merely suck the juices, but an 

 which they deposit great numbers of eggs, known as 

 " fly-blows," whence will issue maggots whose one busi- 

 ness will be to demolish the solid parts. Thus each 



