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 pupse 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 remarljable 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, maxillK, 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 peduncle 

 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 of 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 Uke oars. These insects may be 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 bubbles 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 Libellulae. [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."] 



Fabricius, preceded in this respect by Reau- 

 mur, divided the Dragon-flies into three genera. 



Libellula 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 larvas 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. caiirel- 

 lafa, here figured, the males in both of which 



are remarkable for the fine leaden-blue colour Fig. 105.— Libciiuin c.mceiiata 



of their abdomen]. The memoir of Van der Linden on the Libellula; of Bologna, and subsequently upon those 

 of Europe, as well as tlie Hor^ Entomologies; of i\L Charpentier, and a series of memoirs by M. Boyer de Fonsco- 

 lombe in the Annales de la Socicte Entomologiqite de France, may be consulted. The British species, distributed 

 into various genera, have been described by Mr. Stephens.] 



^Eshna, 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 

 sijine ; the abdomen is always long, narrow, and cylindric. The body of the larvae and pup.-c 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. Libellula 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. 



