a 
NEUROPTERA. — EPHEMERID. 27 
as to make the tarsi appear 4-jointed, as, indeed, they have been de- 
scribed by some authors), and terminated by a large oval pulvilius, 
and a single broad notched claw. 
Dr. Leach formed these insects, in his MSS. (quoted by Stephens, 
Syst. Cat. p.305.), into a separate order, named Anisoptera, from the 
unequal size of the wings. 
Cuvier, followed by Duméril, united them together with the Phry- 
ganeee, into a distinct section of the order, termed Agnathes, from the 
rudimental structure of the mouth, destitute of jaws; whilst Brullé 
united them with Libellula and Termes inte a separate order, which 
he named Dictyoptera. 
These insects have obtained their name Ephemera, from the Greek 
Egnpepoc, diurnal, in allusion to the extremely short space of time* 
which they occupy as perfect insects. Their elegant flight in swarms 
(composed, as in the gnats, almost entirely of male insects) in fine 
afternoons, over or near water, alternately rising and falling, must have 
attracted the attention of the most incurious: in this operation the up- 
ward flight is produced by the repeated action of the wings; but in 
descending, the wings are widely extended, as well as the tails. A 
few hours previously, they had been the inhabitants of the water, from 
which, in the pupa state, they had crawled to the surface, where they 
cast off their pupa skin, appearing at first sight to be fully developed, 
with the wings extended to their full size (which state is termed by 
Mr. Curtis the pseudimago) ; they then make their way, flying with 
difficulty, to the shore, where they affix themselves to the trunks of 
trees, stems of rushes, walls, or even upon persons standing upon the 
bank, when they again cast off a very delicate pellicle, in which 
they had been entirely encased, and which remains, unchanged in 
form, attached to the objects on which they had stationed themselves : 
the skin, however, in which the wings had been enclosed, shrivels and 
curls up into a mass, hanging down at the sides of the thorax ; after 
this process, the wings, disengaged from the outer covering, assume a 
brighter appearance, und the tails grow to twice their previous length. 
* De Geer kept Ephemera vespertina alive for eight days; and Mr. Stephens 
mentions having kept specimens of Cloeon dipterum alive above three weeks. Had 
these individuals, however, been at large, and capable of pursuing their natural habits, 
I doubt not that their existence would have been as short as that of their companions. 
Dr. Franklin’s beautiful address, supposed to have been delivered by an “ ancient 
Ephemera,” which had lived four hundred and twenty minutes, is one of the most 
profound lessons to humanity ever published. 
