DIPTERA. 491 



mother on the substances that are to serve for the food of her 

 young. Some flesh-liies produce their young alive, or abeady 

 hatclicd, and drop them on the dead and putrefying animal 

 matter, which they are to consume and remove in the shortest 

 possible time. An exception from the usual course among 

 insects appears therefore to have been made in favor of these 

 viviparous flesh-flies, to enable their young promptly to per- 

 form their appointed tasks. These insects produce an immense 

 number of young, as many as twenty thousand having been 

 observed by Reaumur in a single fly.* Our largest viviparous 

 flesh-fly is the Sarcophag-a Georg-ina of Wiedemann. It ap- 

 pears towards the end of June, and continues till the middle 

 of August, or perhaps later. Its face is silvery white, and 

 there is an oblong square black spot between the eyes, which 

 are copper-colored. The thorax is light gray, with seven black 

 stripes upon it. The hind body is nearly conical, has the lus- 

 tre of satin, and is checkered with square spots of black and 

 white, shifting or interchanging their colors according to the 

 light wherein they are seen. The legs are black, and the hind- 

 most pair are very hairy in the males. The female is about 

 half an inch long; the male is rather smaller. In the Sarcopha- 

 gans, or flesh-eaters, as the name implies, the bristles on the 

 antennte are feathered. 



The flies that aboimd in stables in August and September, 

 and sometimes enter houses on the approach of rain, might be 

 mistaken for house-flies, were it not for the severity of their 

 bites, which are often felt through our clothing, and are gen- 

 erally followed by blood. Upon examination they will be 

 found to difler essentially from house-flies in their proboscis, 

 which is very long and slender, and projects horizontally be- 

 yond the head. The bristles on their antennas are feathered 

 above. Cattle sutFer sorely from the piercing bites of these 

 flies, and horses are sometimes so much tormented and enraged 

 by them as to become entirely ungovernable in harness. The 

 name of this kind of fly is Stomoxys calcitrans; the first word 

 signifying sharp-mouthed, and the second kicking, given to the 



* " Memoires," Vol. IV., p. 417. 



