62 ‘INSECTA. 
The other Subulicornes have an entirely membranous or very soft 
mouth, composed of parts that are ratherdndistinct. Their tarsi 
consist of five joints; their inferior wings are much smaller than the 
superior, or even wanting, and their abdomen is-terminated by two 
or three sete. ° «+ ‘ eae 
They form the genus, nif 
ErHeMera, Lin. 
So called from their short term of life, in their perfect state. Their 
body is extremely soft, long, tapering, and terminated posteriorly by, 
two or three long‘and articulated sete. ‘The antenne are very small 
and composed of three joints, the last of which is very long, and in 
the form of a conical thread. The anterior part of their head pro- 
jects in the manner of a clypeus, frequently carinated and emargi- 
nated, covers the mouth, the organs of which are so soft and exigu- 
ous that they cannot be distinguished. The wings of those Insects 
are always'placed perpendicularly, or slightly inclined posteriorly, 
like those of an Agrion. The legs, are yery slender, and the tibia 
very short, and almost confounded with the tarsi, which frequently 
present but four joints, the first having nearly disappeared; the . 
two hooks of the last one are strongly’compressed into the form of a_ 
little palette; the two anterior legs, much shorter than the others, 
are inserted almost under the head and directed forwards. © 
‘The Ephemerz usually appear at sunset, in fine weather, in sum-~ 
‘mer and autumn, along the banks of rivers, lakes, &c., and some- 
times in such innumerable hosts that after ‘here death the surface 
of the ground is thickly covered with their bodies; in certain’ dis- 
tricts cart-loads of them are collected for manure... © 7 
‘The descent of a. particular species—the albipennis—remarkable 
for the shortness of its wings, recals to our minds a heayy fall of 
snow in winter. ; hae 
These Insects collect in flocks in the air, flitting about and balanc- 
ing themselves in the manner of the Tipulz, with the terminal fila- 
ments of their tail divergent. There the sexes unite. The males 
are distinguished from the females by two articulated hooks at the. - 
extremity of their abdomen, with which they seize them. It also 
appears that their anterior legs and caudal filaments are longer than 
those of the females, and that their eyes are lar gert. some of them 
even ve four cote a eyes, two of which are elevated and much 
sexual differences are carefully indicated, works that have greatly: facilitated the 
disentangling a their aanany, ' 
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