VAEIODS FLIES. 173 



bottom of stagnant pools or cisterns, and the re- 

 spiration is carried on through the telescopic tail, 

 which is long enough to protrude through the mud, and 

 to convey the necessary oxygen to the system through 

 two flexible air-tubes that pass through the " tail ". 



It will be remembered that in mentioning the 

 Green Oak Moth, the Destroying Empis was also 

 noticed. One of these flies is shown on plate J, fig. 

 5, with the poor Tortrix in its grasp. Plate K, fig. 

 1, shows its foot, and fig. 3 its head, together with 

 its long beak. 



The beak of this fly somewhat reminds one of the 

 corresponding portion of the Gnat, which insect is 

 not itself depicted, though on plate F, fig. 10, is 

 shown the wonderful little egg-boat which it makes. 

 This insect glues together its eggs in such a manner 

 that they are formed into a true lifeboat, which 

 cannot be upset, or sunk, or filled with water, but 

 floats securely on the surface until the young are 

 hatched. That object accomplished, the gnat-larvae 

 tumble into the water, and there undergo their 

 transformation. 



The last of the two- winged flies that will be men- 

 tioned is the common Daddy Long Legs, or Crane- 

 fly, which seems to set such little value on its limbs. 

 It is a very injurious insect in its larval state, feeding 

 on roots, and doing great damage. Plate H, fig. 1, 

 shows a very pretty species, covered with yellow rings. 



Every one must have noticed the beautiful and 

 12 



