290 SYSTEMATIC ARRANGEMENT 



in most cases, are short and slender, the tarsi vary- 

 ing in the number of joints from three (their amount 

 in dragon flies,) to five (as among the Hemerobii, 

 &c.) 



The transformations of this order differ in their 

 nature in different tribes, some undergoing a semi- 

 metamorphosis, others a complete one. The larvae 

 are constantly provided with six feet, and many of 

 them reside in the water. The majority of the larvae, 

 as well as of the perfect insects, are carnivorous; a 

 few are omnivorous in all their states. 



We have upwards of 200 Neuropterous species 

 in Britain, and of these certain of the Libellulae are 

 among the largest insects found in this country. 



Latreille divides this order into two primary groups, 

 discriminated by the shape of the antennae : SABU- 

 LICORNES, having these organs minute and setiform, 

 with not more than seven joints ; FILICORNES, having 

 long antennae, composed of numerous joints, and for 

 the most part filiform. The former section compre- 

 hends the families Libellulidae (Dragon-flies,) and 

 Ephemeridae (May-flies;) the latter contains the 

 Panorpidae, (Scorpion-flies,) Myrmeleonidae, (AnU 

 faws,)Hemerobiidae, (Day-flies,) Termitidae, (White- 

 ants,) Raphidiidae, Psocidae, Perlidae. 



The dragon- flies are well known insects, owing 

 to their large size, frequent occurrence, and their 

 beautiful and varied colouring. Such of them as 

 are now referred to the old genus Libellula, may be 

 recognised by having their wings extended horizon- 

 tally during repose ; a vesicular elevation on the 



