154 STATES OF INSECTS. (Larva.) 
larva as well as the pupa and imago of Ephemera is fur- 
nished with three long diverging multiarticulate tails, 
which are probably useful as a kind of rudder to assist 
and direct their motions. ‘That of the smaller dragon 
flies (Agrion) is furnished with three long vertical lamine, 
by moving which, as fish do their tails, from side to side, 
the animal makes its way in the water*. That singular 
one, also, with a hooked head, figured by Reaumur, has 
a single swimming lamina, or fin, shaped like a fan, and 
placed in a vertical position under the tail». 
The whole circumference of the body in some coleo- 
pterous larvee,—for instance, in that of the tortoise-beetle 
lately mentioned,—is surrounded with appendages like 
rays. These are sometimes simple, rough with very 
short spinous points *; but I have a dipterous larva, in 
which these radii themselves are beautifully pinnated by 
a fringe of longish spines on each side. Reaumur has de- 
scribed the grub of a beetle, the genus of which is uncer- 
tain, and which feeds upon the larva of Aleyrodes Cheli- 
donii, whose body is margined on each side by eight tri- 
angular fleshy mammular processes, terminating each in 
a bristle, which give it a remarkable aspect’. The cu- 
rious scent-organs with which the larva of Chrysomela 
Populi is fringed have been before fully described ; and 
therefore I shall only mention them here ¢. 
In the larvee of the lace-winged flies (Hemerobius), and 
ant-lions (Myrmeleon), the anus is furnished with a smalk 
fleshy retractile cylinder, from which proceeds the silken 
* De Geer ii. 697. t. xxi. f. 4, 5. 6 8 6. 
> Reaum. v. ¢. vi. f. 7. 2. 
© Prate XVIII. Fic. 2. 
¢ Reaum. ii, ¢. xxv. f. 20. 
© See above, Vou. II. p. 245—. 
