FIELD BOOK OF PONDS AND STREAMS 



Fig. 237. — I, Drone-fl}^ Eristalis tenax; 2, its 

 larva, the rat-tailed maggot, showing the tail-like 

 air-tube. 



of the largest and brightest colored of all the Diptera. In 

 some species such as the drone-fly (Fig. 237) they look so 

 much like honey-bees that they are easily mistaken for them. 

 Larvae. — The larv^ae are found in all sorts of materials and 

 places, water, decaying wood, in fungi, and in the nests of 

 ants and bees. This larva of the drone-fly (Fig. 237) lives 

 in foul water where it feeds on decaying organic matter. It 

 was named "rat-tailed maggot" because of the long tail- 

 like air-tube which can be extended to the surface when the 

 larva is immersed in water or in decaying muck. This tele- 

 scopic tube is composed of two segments, one of which can 

 be slipped over the other; at its tip there is a rosette of hairs 

 which keep water out of the air-tube. The body of the 

 larva is about half an inch long. The larval skin contracts 

 to form the dark homy pupal case. 



300 



