CHAP. IX. DESCRIPTION OF THE ORDER OF INSECTS. 51 



from which they are at once distinguished by the prominent 

 anal forceps. 



NEUROPTERA (Dragon-flies, May-flies, etc*) These insects 

 are mostly provided with four membraneous wings (such as 

 the Dragon-fly, Fig. 143), but in a few species the posterior 

 wings are wanting, while several others are entirely wingless. 

 The wings, when present, are usually supplied with numerous 

 cross- veins, so as to form a network, but in several species 

 (such as in the Genus Psocus, Fig. 144), the cross- veins are 

 not more numerous than they are in the wings of Butterflies 

 and Moths. The body and its appendages are commonly soft 



Fig. 145. 



. ^L 



Fig. 144. 



and weak, and the tip of the abdomen is sometimes furnished 

 with two or three long bristles (setae.) The mouth-parts are 

 fitted for biting. The larvae are mostly aquatic and are pro- 

 vided with six legs; in some the transformations are incom- 

 plete, the pupa being active (as the pupa of the Dragon-fly, 

 Fig. 145); in others they are complete, and the pupa has the 

 legs, etc., enclosed in separate sheaths; several pupae of the 

 latter kind are active, to a certain extent, just before the 

 perfect insect emerges. With the exception of the White 

 Ants, the insects belonging to this Order cannot be regarded 

 as injurious, while several species are eminently beneficial 

 (such as the laced-winged Flies, Fig. 21). Some authors have 

 separated those insects belonging to this Order which pass 

 through an incomplete transformation, into a distinct Sub- 

 order, which they call Pseudo-neuroptem; but this course has 

 not been generally followed. 



