i8 INSECTS 



A very decided advance is found in those insects 

 that gain their food by sucking it through a jointed 

 beak by means of slender, bristle-Uke lancets in all 

 stages; and these are the Hemiptera or true bugs. 



Grasshoppers, roaches, crickets and the like have 

 the hind wings folded in longitudinal plaits, laid straight 

 under the covering primaries, and are hence called 

 Orthoptera. They chew their food and are often trouble- 

 some to the agriculturist. 



Another large series has the wings thin, transparent, 

 usually of good size, with numerous longitudinal and 

 transverse veins like a net or reticule and hence called 

 Neuroptera. This is the most primitive of the winged 

 orders of biting insects, and shows a great diversity of 

 forms and grades of development. The dragon flies 

 serve as a well-known illustration of one type. The 

 very general definition of the order here given covers a 

 series of remnants that are elsewhere more particularly 

 specified. It was in the Neuropterous or net-winged 

 type that the great break-up among the mandibulate 

 insects occurred and variation ran in many directions. 

 Some of the lines flourished for a little time only; they 

 proved ill adapted to their surroundings and survive 

 only by a few families and genera in which the species 

 are usually well fixed and easily distinguished. Others, 

 well suited to live, proved barren when it came to adapt- 

 ing themselves to new or a variety of conditions. These 

 are fairly numerous even now in families, genera and 

 species; but their limit of adaptation is reached and 

 they are shoots from which no further branches may 

 be expected. From the other lines the modern domi- 

 nant orders developed which, rich in forms, show 

 species capable of living under the greatest conceivable 

 variety of conditions. 



The Coleoptera or beetles are known by the hard 



