1884.] Entomology. 631 
times to a considerable elevation, presently making its way to trees, 
walls or herbage, &c., likely to afford it a suitable resting place. 
it assumes the posture characteristic of its genus during re- 
pose. It may stand either upon all of its feet, or upon only the two 
hinder pairs; and the fore legs extended in advance, off the ground, 
may in this last case be held either close together or else apart 
from each other. The caudal setz, in most instances divergent, 
are sometimes placed alongside of one another horizontally, or 
slanting upward. 
The mode of flight of these graceful creatures is then described; 
usually, especially in the males, consisting of an intermittent ac- 
tion of the wings, which “ results in a dance-like motion almost 
vertically up and down,—a fluttering swift ascent. and then a 
passive, leisurely fall, many times repeated.” Other habits and 
occasional swarming of certain May-flies are referred to, 
and their reproductive habits. 
The facts regarding oviposition, must, we think be new to our 
readers. “ Some short-lived species discharge the contents of their 
ovaries completely e masse, and the pair of fusiform or subcylindri- 
cal egg-clusters laid upon the water rapidly disintegrate, so as to let 
the egg sink broadcast upon the river-bed. The less perishable 
Species extrude their eggs gradually, part at a time, and deposit 
in one or the other of the following manners:—either the 
mother alights upon the water at intervals to wash off the eggs 
that issued from the mouth of the oviducts during her flight; or 
else she creeps down into the water—enclosed in a film of air, 
with her wings collapsed so as to overlie the abdomen in the form of 
‘nacute narrowly linear bundle, and with her sete closed together 
~to lay her €ggs upon the underside of stones, disposing them 
‘a rounded patches, in a single layer evenly spread, and in mutual 
the euity. This has been witnessed by me several times, and in 
a ae of several species of Baëtis. The female on the comple- 
“on of her labor usually floats up to the surface of the water, 
all at vely swimming with her legs, and, on emerging, her wings 
flies a © are suddenly unfolded and erected; she then either 
Pg Y, Or (as often happens) if her setæ have chanced to be- 
~ Wet and cannot become extricated from the water, she is 
iver ard them until she is drowned. In some instances, how- 
| ' the female dies under water beside her eggs.” 
elipti e are indefinitely numerous, some subrotund, others 
oo 1 
| — L. Calori (1848) and Dr. E. Joly 1 1877) have 
derum, oa of larviparition observed by them in Cloéon dip- : 
from + though they supposed that the young were produced 
- Some week hated eggs retained within the mother, perhaps for 
Sility a: it may be conjectured with equal, if not greater prob 
T , €se were the produce of unfertilized ova advanced 
