DIPTEEA. 



these insects are also infinitely modified in order to adapt them to 

 their various functions. 



M. Macquart divides the Musddes into three sections : the 

 Creophili, the Anthomyzides, and the Acalyptera. 



The Creophili have the strongest organisation ; their movements 

 and their flight are rapid. The greater part feed on the juices 

 of flowers, some on the blood 

 or the humours of animals. 

 Some deposit their eggs on 

 different kinds of insects, 

 others on bodies in a state of 

 decomposition, some again are 

 viviparous. The insects of the 

 genus Echinomyia, for instance 

 (Fig. 51), derive their nourish- 

 ment from flowers. They de- 

 posit their eggs on caterpillars, 

 and the young larvae on hatch- 

 ing penetrate their bodies and 

 feed on their viscera. How 

 surprised, sometimes, is the 

 naturalist, who, after carefully 

 preserving a chrysalis, and 

 awaiting day by day the 

 appearance of the beautiful 

 butterfly of which it is the 

 coarse and mysterious enve- 

 lope, sees a cloud of flies 

 emerge in place of it ! 



But there is another singular manoeuvre performed by some of 

 the species of the Diptera, with which we are at present occupied, 

 to prepare an abundant supply of provision for their larvae as soon 

 as they are hatched. The following are the means they employ. 



It is well known that certain digging insects, such as bees, 

 weevils, flies, &c., carry their prey, other insects which they 

 have caught, and which they intend should serve as food 

 for their own larvae, into their subterranean abodes. These Diptera 

 spying a favourable moment, slip furtively into their retreats, and 



Fig. 51. Ecliinomyia grossa. 



