ORTHOPTERA OF INDIANA. 139 



The eerci of the female are much smaller than those of the male, 

 and in other Orthoptera are often wanting. The tergnm or upper 

 portion of the tenth abdominal segment is a triangular, often thick 

 solid plate, known as the '"supra-anaV plate. At the base of this 

 plate and resting upon it, a pair of small projections, known as 

 "fwcida" are usually present. In certain genera of locusts the shape, 

 size and relative position of these afford valuable specific characters. 

 The above constitute the more important external parts of the 

 locust, the characters of which are used in determining the name of 

 a member of the order Orthoptera. As will be seen in the pages 

 which follow, these different parts vary much in size and in form, 

 but the names given to them apply as well to the members of one 

 family as to another. By referring to the accompanying figures, and 

 by observing carefully the parts of the specimen in hand, the begin- 

 ner need have little hesitation in deciding as to whether the descrip- 

 tion agrees with that specimen. 



INSECTS OF THE ORDER ORTHOPTERA. 



All true insects can be separated into two great groups, based upon 

 the kind of changes or transformations which they undergo before 

 reaching the adult or winged stage. To one group — the Mefahola — 

 belong those insects which undergo what is termed a complete meta- 

 morphosis. In this group there are four distinct stages — ^the egg, 

 larval, pupal and imago — in the order named. No insect is hatched 

 from the egg with wings, and when an insect reaches the winged 

 stage it is adult, and never grows thereafter. Thus the gnats and 

 midges are not the sons and daughters of the larger flies, but are 

 full grown insects of themselves, which are undergoing the fourth 

 or last stage of their lives. The second, the larval or wormlike stage, 

 is the one in which the insect of this group is commonly the most 

 injurious, for then it eats voraciously, and then is the only period 

 of its life when it grows in size. The pupal, or third stage, is usually 

 a quiescent one, the insect eating nothing and not increasing in size, 

 but undergoing great changes of form. Thus the homely and often 

 repulsive grubs, maggots and caterpillars, which are the larval forms 

 of the beetles, flies and butterflies, respectively, enter the third stage 

 as wormlike crawling creature^, and emerge from it as beautiful 

 winged forms, sometimes glistening and gleaming with all the colors 

 of the rainbow. This change of life and form is undoubtedly of 

 great advantage to the most of this group of insects, as it tends to 

 prevent the extinction of the species; since, if at a given moment 

 the parents were swept out of existence, the young, living in a differ- 

 ent station, would continue to represent the species. 



