ALLIES OF THE RED-LEGGED GRASSHOPPER 23 



approach its prey or to escape notice while waiting for food, 

 it may be classed as an example of aggressive resemblance. 

 This term covers those cases where an animal, in resembling 

 its immediate environment, either in shape or color, or both, 

 is thought thereby to be assisted in attack on its prey. 



Several species of mantids from India resemble different 

 flowers which are visited by insects, and seize upon such 

 unwary visitors as do not detect the imposition. In this 

 case the resemblance is to an object attractive to the prey, 

 and may be spoken of as alluring coloration. 



Definition of Orthoptera (Gr. orthos, "straight"; pteron, 

 "wing"). All the insects mentioned in this chapter have the 

 mouth parts adapted to chewing, and most of them have 

 two pairs of wings. The posterior wings, when present, are 

 folded lengthwise like a fan beneath the hardened anterior 

 wings, and are thus protected from injury. 



The newly hatched individual grows to the adult condi- 

 tion without any abrupt or conspicuous changes in form. 

 There is an evident increase in size each time the skin is 

 shed in the process of molting. The imagoes differ from the 

 nymphs chiefly in their larger size and the presence of 

 wings. This type of development in which the newly 

 hatched young gradually changes or transforms into the 

 adult is called incomplete metamorphosis. On account 

 of these common characteristics these insects are united 

 in a group, or order, called Orthop'tera, in allusion to the 

 longitudinal folding of the posterior pair of wings. 



The chewing mouth parts with which the Orthoptera are 

 provided make them especially destructive to vegetation, 

 for they feed very largely on plants. Consequently many 

 members of the group are crop destroyers. Crickets and 

 cockroaches if given the opportunity become serious house- 

 hold pests. Many members of the order seem to have no 

 direct economic importance. 



