J 



GROWTH AND TRANSFORMATIONS OF INSECTS 53 



from the thorax. In another week the skin is shed for a fourth 

 time, and the fifth stage is easily recognized as a full-grown nymph, 



being one third inch long, and 

 the wing pads and thorax 

 being much enlarged. After 

 feeding for another nine days 

 it molts for the last time and 

 transforms to the winged adult, 

 the whole growth having re- 

 quired from four to five weeks. 

 Adult. The new adults be- 

 come numerous in August, but 

 neither mate nor lay any eggs 

 during that season, continuing 

 to feed until the first frosts of 

 autumn blacken the leaves, 

 when they rapidly disappear 

 into winter quarters. 1 During 

 the middle of the day they fly 

 here and there in search of 

 suitable hibernating places, and 

 finally hide along the edges of 

 FIG. 66. First three stages of the nymphs woo dlands, or beneath leaves, 



of the differential locust. (Much enlarged) . 



under logs, boards, or whatever 



shelter may be adjacent to the garden, where they remain dormant 

 until called back to activity by the warm sunshine of late spring. 

 Life history of the differential locust (Melanoplus differ entialis). 

 Incomplete metamorphosis. Through- 

 out the Mississippi Valley, from Illi- 

 nois southward, the differential locust 

 is one of the most common and de- 

 structive grasshoppers, and is an excel- 

 lent example of several of our more 

 abundant and injurious species whose 

 life histories and feeding habits are, in general, very similar. 



1 The life history as given is for New England ; farther south the transforma- 

 tions take place earlier and more rapidly, and in the extreme south there may be 

 more than one generation. 



FIG. 67. Egg mass of the 

 differential locust 



