DIPT ERA. S^ 



this digging is visible, as those places become by degrees transparent. 

 Each blow detaches a small portion of the substance of the leaf. It 

 is thus that these miners hollow out galleries for themselves, in which 

 they find shelter, food, and security. Some are changed into pupce in 

 the gallery which they have hollowed out, others go out of the leaves 

 when they are near their final transformation. 



Section of Acalyptera. — The Acalyptera, which are the last of the 

 ;reat tribe of Ahiscidcs, comprehend the greater number of these 

 nsects. Their constitution appears 

 be peculiar and slow. They live 

 principally in the thickest part of 

 voods, on grasses, and aquatic plants. 

 Fearing the lustre and warmth of the 

 jun, they never draw the nectar from 

 .lowers. Their flight is feeble, and 

 ,hey never indulge in those joyous 

 ethereal dances which we have men- 

 ioned when speaking of the preceding 

 ,;roups. Their life is generally melan- 

 choly, obscure, and hidden. Some 

 ;)f them seek decomposed animal and 

 fcgetable substances, others living 

 vegetables. 



i We shall only be able in this im- 

 nense group of Miiscidce to mention 

 ^ few types which are interesting from 

 farious reasons, such as the HeloinyzcE, 

 jhe Scaiophagce^ the Ortalides, the Dad, 

 ■md the ThyreophorcB. 

 ' The Helojiiyzce (Fig. 64) live in 

 ^e woods. Their larv^ are deve- 

 bped in the interior of fungi. Re'au- 

 nur studied the larvas of the Truffle 

 ielomyza. The head of this fly is 

 ,irruginous, its thorax is of a brownish 

 ^rey, its shoulders of a brownish yel- 

 pw, its wings brownish, the abdornen 

 fCllow and brown, and the feet red. 

 ^he larvje of these insects commit depredations for which gourmands 

 /ill never forgive them, destroying, as they do, their truflles. When 

 ;ne presses between one's fingers a trufile that is in a too advanced 

 ^te, one feels certain soft parts, which yield under pressure. On 



Fig. 64. — A species of Helomyza. 



