NEUROPTERA. 
61 
canal, is almost always full of air-bubbles ; I catch one 
of those dancing males, which I recognize by his very 
long fore-legs, extended so that one might at first sight 
mistake them for antennae ; I press him quickly in the 
middle ; crack he goes ! for the air-bubbles have burst 
by the pressure. No wonder that Ephemera’s stomach 
is empty, for, as a fact, he has no real mouth; there is 
no passage from the mouth to the stomach. But though 
the stomach is full of air, we must not suppose that 
Ephemera suffers at all from flatulence. The air in the 
intestinal canal, there can be no doubt, serves the pur¬ 
pose of a balloon and helps to buoy the insect up, and 
saves the expenditure of muscular force ; for as no food 
is taken to supply the waste, the muscles are not capable 
of long-sustained action. 
The peculiar up-and-down flight of the May-flies 
must be familiar to everyone. In groups they love to 
practice their up-and-down flight; with head erect and 
bodies prettily curving upwards they exercise their 
characteristic dance, especially when the sun shines 
brightly and the air is still. But I must here notice 
that it is the males that exercise this particular style of 
dance, rising up sometimes ten or twelve feet, then 
dropping down again suddenly the same distance ; at 
least I think this dance, as a rule, is strictly confined 
to the gentlemen, for 1 have never detected a lady 
May-fly in her marbled dress of white and brown 
amongst the company. 
I should mention that the “Green-drake” of the 
Fly-fisher is the sub-imago stage of the May-fly, while 
the “ Grey-drake” is the perfect imago female. It is in 
their sub-imago state that so many thousands fall 
