158 INSECT TRANSFORMATIONS. 



The preceding grub may occasionally be found in 

 shallow ditches, and about the edges of ponds, in 

 summer; but a remarkable larva, with a very dif- 

 ferent apparatus for breathing, is much more common 

 in similar situations, and also in the open drains from 

 dunghills, &c. The latter is the maggot of a two- 

 w,inged, bee-like fly (Helophilus pendulus, MEIGEN), 

 and from its shape is appropriately termed rat-tailed 

 by Reaumur. The tail is the part of the grub which 

 most merits attention, being formed somewhat after the 

 telescopic model of the ovipositor of the breeze flies,* 



a b c 



Telescopic-tailed water larvae, n, a glass vessel of water containing 

 the larvae, natural size, i, magnified view of the tail, with the breath- 

 ing tube partially contracted, c, a still more enlarged view of the tail. 



* See Insect Architecture, p. 403. 



