404 TRANSFORMATIONS OF INSECTS. 
are called “fly blows,” increase in size with very great rapidity 
if they have sufficient food; and there is some truth in the 
THE METAMORPHOSES OF THE MEA’ FLIES, 
(Calliphora vomitoria and Sarcophaga carnaria.) 
saying that a pair of maggots will eat up a carcase as soon as 
a lion, for the reproductive powers of the female are enormous. 
The Bot Flies are very extraordinary creatures. They are 
large velvety flies, which have very small antenne and a rudi- 
