INTRODUCTION. 



DARLINGTON 

 PU3LIC LIBRARY, 



An insect is an articulate animal (i.e., an animal com- 

 posed of segments or rings), lireathingby means of tracheae, 

 or air tubes, having the body divided into three distinct 

 parts (head, thorax, and abdomen), and furnished in the 

 perfect state with six legs, two antennae, and (with isolated 

 exceptions) two compound eyes. In the course of develop- 

 ment it passes tlirough various metamorphoses, and when 

 perfect is usually winged. 



Insects are distrilnited into several orders, among which 

 the Coleopteni, or Beetles, are characterized by the posses- 

 sion of four wings, viz., an anterior pair of horny or leathery 

 consistence (generally covering the posterior wings when 

 at rest, horizontal, and united by a straight suture), and a 

 memliranous posterior pair, folded when not in use ; by a 

 mouth with transversely moveable jaws; and by the pupa 

 being neither active (as in the grasshoppers and bugs), nor 

 covered and entirely concealed by an opaque case (as in 

 the moths), but enclosed in a thin skin, revealing beneath 

 it the parts of the perfect insect. The first of tliese 

 characteristics is, however, not invariable, the posterior 

 pair of wings being sometimes absent, at others not covered 

 by anterior pair, which latter are occasionally (e.g., Meloe) 

 not united by a straight suture, while in some cases (e.g., 

 female of Lampp-is) both pairs of wings are absent. 



A beetle on leaving the egg passes through the state of 

 kora and ^JW|ja before emerging as a perfect insect (imago). 

 The larva varies in form, is usually long and narrow, 

 divided into twelve segments, besides the horny head. 

 The three segments next to the head corres]X)nd to the 



