NEUROPTERA. 
575 
according to the species, and which have been carefully studied by Messrs. Van der Linden and 
Charpentier ; the legs short, and directed forwards. 
The female, in order to deposit her eggs, places herself upon plants close to the edge of the water, 
into which she repeatedly thrusts the extremity of her body. The larvae and pupae reside in the water 
until the period of their final transformation, and are somewhat like the perfect insect, except in 
wanting wings. But the head, upon which we perceive no ocelli, is remarkable for the singular form 
of the piece which occupies the place of the lower lip. This is a kind of mask, covering the mandi- 
bles, maxillae, and nearly all the under side of the head. It is composed, 1st, of a principal triangular 
piece, which Reaumur calls the mentonniere, and which articulates by a hinge with a pedunele 
attached to the head ; 2nd, of two other pieces inserted at the lateral and anterior angles of the pre- 
ceding piece, moveable at the base, transverse, and entire, in the form of broad and denticulated 
plates, similar, in their mode oi closing the mouth, to a pair of shutters, or in the form of small 
hooks. The insect is able to close or extend this very quickly, seizing its prey by means of the claws 
at its upper part. The posterior part of the abdomen is sometimes furnished with five unequal-sized 
conical plates, capable of opening or closing, and forming a kind of pyramidal tail, and sometimes 
with three elongated villose plates like oars. These insects may he seen every instant opening the 
rectum in order to take in a supply of air, when they close it again, and shortly afterwards eject the 
water with force and mingled with hubbies of air, this action appearing to assist them in their motions. 
[Its more immediate object is, however, in order to obtain a supply of fresh oxygen from the water 
thus introduced into the rectum.] When arrived at the period for their final change the pupae quit 
the water, crawl up some adjacent stem, where they fix themselves by their claws, and scale off their 
pupa-skin. 
M. Poey, who has particularly studied the insects of Cuba, has informed me, that at a certain season 
of the year the northerly winds bring to the city of Havannah and its neighbourhood an innumerable 
quantity of specimens of one of the spe- 
cies of Libellulse. [Other instances of 
their periodical flight or migrations in Eu- 
rope have been observed. See Dr. Weis- 
senborn’s memoir on this subject in the 
new series of the Mag. of Nat. Hist.l 
Fabricius, preceded in this respect by Reau- 
mur, divided the Dragon-flies into three genera. 
Lihellula proper, has the wings extended 
horizontally in repose ; the head nearly globu- 
lar, with the eyes very large ; a vesicular eleva- 
tion, having on each side an ocellus, upon the 
vertex ; the other ocellus, or the anterior one, 
is much larger, and the middle division of the 
lower lip much smaller, than the lateral ones, 
which, closing by a straight suture, exactly 
shut the mouth. The abdomen is generally 
broad and flat. The larvae and pupae have five 
appendages at the extremity of the body, which 
is short. Type, L. depressa, Linn., [a very 
common British species, as well as L. cancel- 
lata, here figured, the males in both of which 
are remarkable for the fine leaden-blue colour Fig. io5.~Libeliuia canceilata. 
of their abdomen]. The memoir of Van der Linden on the Libellulae of Bologna, and subsequently upon those 
of Europe, as well as the Hor<e Entomologicce of M. Charpentier, and a series of memoirs by M. Boyer de Fonsco- 
lombe in the Annates de la Societe Entomologiqiie de France, may be consulted. The British species, distributed 
into various genera, have been described by Mr. Stephens.] 
AEshna, Fabr., is similar to Libellula in the manner in which the wings are carried when at rest, and in the form 
of the head, but in which the two posterior ocelli are situated upon a simple transverse elevation, having, more- 
over, the middle lobe of the lower lip larger, and the two others wide apart, and armed with a strong tooth or 
spine ; the abdomen is always long, narrow, and cylindric. The body of the larvae and pupae is also more elongate 
than in those of Libellula ; the mask is flat, with its two hooks narrow, and armed with a moveable hook at the 
tip. Lihellida grandis, [a common English species, two inches and a half long, and many others]. They fly with 
astonishing rapidity over the margin of waters, pursuing flies and other insects in the same manner as swallows. 
