76 THE LIFE-STORY OF INSECTS [CH. 



In agreement with this manner of life, the cuticle is 

 roughly granulated, often greenish or reddish in hue, 

 and the maggot, despite its want of definite head 

 and sense organs, moves actively and purposefully 

 about, often rearing up on its broad tail-end with an 

 aphid victim impaled on its mouth-hooks. 



In a previous chapter reference was made to 

 the exopterygote insects, stone-flies, dragon-flies, and 

 may-flies, whose preparatory stages live in the water. 

 Among the endopterygote orders many Neuroptera 

 and Coleoptera, all Trichoptera, a very few Lepi- 

 doptera and many Diptera, have aquatic larvae. One 

 or two examples of the adaptations of dipteran larvae 

 to life in the water may well bring the present chapter 

 to a close. Many members of ' the hover-fly family 

 (Syrphidae) have maggots with the tail-spiracles 

 situated at the end of a prominent tubular process. 

 Among the best-known of syrphid flies are the drone- 

 flies (Eristalis), often seen hovering over flowers, and 

 presenting a curious likeness to hairy bees. The 

 larva of Eristalis is one of the most remarkable in 

 the whole order, the 'Rat-tailed maggot' found in the 

 stagnant water of ditches and pools. It has a cylin- 

 drical body with the hinder end drawn out into a 

 long telescopic tube, a more slender terminal section 

 being capable of withdrawal into, or protrusion from, 

 a thicker basal portion. At the extremity of the 

 slender tube is a crown of sharp processes, forming 



