16 OUR INSECT FRIENDS AND FOES 



These insects all undergo incomplete meta- 

 morphosis, and are characterized by having 

 anterior wings of leathery texture, and much 

 narrower than the posterior membranous ones, 

 which are often large and fan-shaped. 



7. Order Neuroptera, comprising the Dragon- 

 flies, May-flies, Caddis-flies, Termites or so- 

 called White Ants, Thrips, and those curious 

 primitive forms of insect life, the Thysanura and 

 Collembola. They form a very diverse order of 

 insects, making it extremely difficult to lay down 

 any definite characters as being common to all. 

 This is partly due to the fact that many insects 

 now included in the Neuroptera, were formerly 

 placed in separate Orders. So we find some 

 members of the Order passing through a com- 

 plete metamorphosis, while in others it is incom- 

 plete. Some, like the Termites or White Ants, 

 are social, others, again, are of solitary or 

 gregarious habits. Nearly all are carnivorous, 

 and they have a practically world-wide distribu- 

 tion, from the tropics to the Arctic Circle. 



The class Arachnida, which forms a connect- 

 ing link between the Insects and the Crustacea, 

 includes the Scorpions, Spiders, Mites, and Ticks, 

 constituting a much less homogeneous group of 

 creatures than the true Insects, and presenting 

 considerable diversity in structure and mode of 

 life. While many of the Arachnida undergo in- 

 complete metamorphosis in which both larva and 

 nymph are active and bear a close resemblance 

 to the adult, others do not pass through these 

 regular changes, but from time to time shed or 

 moult their skins ; and, as each shedding of the 



