NEUKOl'Tl^KA. PANOKPINA. 4^ 



Order IV.— N E U R O P T E R A. 



Wings all nien)branaceous and reticulated, with numerous areolets, generally 

 four, rarely tAvo, or wanting ; eyes usually large; ocelli two or three ; mouth 

 various ; prothorax distinct, ample ; scapuloe and paraphurue parallel and 

 oblique. Metamorphoses various: larva with six articulate legs, and with 

 strong horny mandibles. 



The contents of this order are so extremely various and diversified, 

 as ahnost to prechide the possibility of drawing up a concise set of 

 characters, that shall embrace every species that legitimately belongs 

 thereto : in some the wings are four in number and alike, and the 

 posterior ones (occasionally) actually exceed the anterior in bulk ; 

 while in other groups they are not only dissimilar to the anterior, in 

 reticulation, &c., but they actually become so much diminished, as 

 in some genera (Cloeon, Caenis, &c.) to disappear ; while again in 

 other genera (Boreus, Atropos, &c.) all the wings are wanting. If 

 we select other characters, the same discrepancy is observable — the 

 antennae, for instance, in Ascalaphus, a foreign genus, are longer 

 than the body and clavate, while in the gigantic Libellulae they are 

 so short and slender, especially at the tip, as to be scarcely visible ; 

 again, in these last insects the mandibles, and in fact all the oral 

 organs, are strongly developed, while in the Ephemeridas they almost 

 totally disappear, the rudiments of a labrum and palpi only being 

 evident : in fine, there appears scarcely an organ but what undergoes 

 the extreme of variation in this Protean order. 



If the structure of these insects is so diversified, their habits are 

 no less so : some of them in the primary stages inhabit the water, 

 others live on trees, beneath bark, &c., but most of them appear to 

 be carnivorous : again, in metamorphoses, there is as much diver- 

 sity, as more particularly noticed under the respective families, and 

 in one group (Ephemeridse) a sort of quadruple metamorphosis takes 

 place. 



From the extremely variable contents of this order, it becomes 

 necessary to subdivide it into various groups before treating of their 

 contents: I shall therefore proceed to notice the first of the indigenous 

 ones, in which one of the genera (Boreus) approaches nearest to the 

 Orthoptera. 



Section I.— PANORPINA. 



Head produced in front in form of a rostrum, or beakj at the apex of which 

 Mandibulata, Vol. VL, Junk 30th, 1835. g 



