I70 NATURAL HISTORY OF AQUATIC INSECTS CH. 



of the ground. As in many other aquatic Diptera, 

 the pupa is notably smaller than the larva. In 

 Dicranota it is only three eighths of an inch long, 

 less than half the length of the larva. 



I have never seen the eggs of Dicranota, but the 

 structure of the glands of the female fly leads me to 

 suppose that they are enveloped in a slimy mass or 

 egg-rope, and laid in water. 



I have described the anatomy of the larva and 

 pupa pretty fully in the Transactions of the Entomo- 

 logical Society (1893). Since the publication of my 

 paper I have ascertained that Dicranota is not at 

 all uncommon in Yorkshire, and probably in other 

 parts of the country also. 



PTYCHOPTERA. 



In shallow muddy pools the larvse and pup?e of 

 species of Ptychoptera are often plentiful. The 

 whitish bodies of the larv'ae can sometimes be seen 

 floating near the surface or lying above the mud, but 

 more frequently the body is buried, and only the tip 

 of the long slender tail protrudes through a small 

 hole. Sometimes the mud is pitted with scores of 

 such holes, like the places in which we find the little 

 red worms called Tubifex. If we dig with a trowel 

 in the mud so pitted, a plentiful supply of the larvae 

 can often be obtained. They are to be found 

 throughout the year, but the pupae occur only in the 

 spring and summer. 



The body of the larva might easily be mistaken 

 for that of an Eristal's, on account of its long and 



