(516 ZOOLOGY SECT. 



many-jointed cerci on the anal segment. Compound eyes and ocelli 

 are sometimes present, sometimes absent. This order includes 

 the " Silver-fish " (Lepisma, Fig. 512), and other genera Japyx, 

 Machilis, Campodea. 



ORDER 2. COLLEMBOLA. 



* Wingless Insecta with an abdomen of six or fewer segments, 

 without paired appendages, but, in most cases, with a peculiar 



springing apparatus on the 

 last or penultimate segment. 

 Compound eyes never present. 

 This order includes the Spring- 

 tails (Podura, Fig. 513) and 

 others. 



FIG. 512. Lepisma. (After Guerin and FIG. 513. Podura. (After 



Percheron.) Guerin and Percheron.) 



Sub-Class II. PTERYGOTA. 



Insects the great majority of which have wings in one or both 

 sexes in the adult condition. A complete or incomplete meta- 

 morphosis. 



ORDER 3. ORTHOPTEROIDEA. 



Insects with incomplete metamorphosis, with biting jaws, and 

 with cerci of varying character at the extremity of the abdomen. 



Sub-order 1. Orthoptera. 



Orthopteroidea in which there are two pairs of wings of which 

 in most cases the anterior pair are harder and more opaque, the 

 posterior pair more delicate and capable of being folded up like 

 a fan beneath the anterior pair. The metamorphosis is incomplete. 



In this sub-order are included a large number of families capable 

 of being arranged in three main groups, viz. (1) the Saltatoria 

 or Leapers (Grasshoppers, Locusts, Fig. 514, and Crickets) ; (2) the 



