346 NATURE SKETCHES IN TEMPERATE AMERICA 



the nymph skin, thereby entering the adult stage. In twenty 

 minutes the body was pigmented with red, the coloration 

 being of the same general character as that of the nymph. 

 The pale, wrinkled wings did not take on the black pigmen- 

 tation immediately, but after one-half hour they gradually 

 stretched out to full length and dried, so that they were 

 finally brought together like a folding fan, and closed to the side. 

 The tegmina, in the meantime, were stiffening and they were 

 aided to the sides by the hind tibiic, and j^ressed together by 

 the femora into their normal straight position. 



Shortly after the moulting of the red individual, the gray 

 nymph referred to also underwent ecdysis. When the resulting 

 adult became fully pigmented within an hour afterward, it 

 was gray like the nymi)h. Though these adult insects assumed 

 the general coloration of the nymphs, they gradually turned 

 darker, so that after a month, August thirtieth, the rust-red 

 individual was deepened into a very dark purplish brown, 

 with a grayish tinge on the upper surface of the bod3% tegmina 

 and pronotum. After the expiration of a similar period, the 

 grayish individual appeared slightly darker than when it first 

 moulted. It must be remembered that these Orthoptera were 

 left exposed to the full out-door sun and air, and fed on grass 

 and other green herbage. On several occasions when it rained, 

 the vivarium was filled with water, driving the locust to the 

 top of the screen, but the water in each instance was soon 

 emptied out. These locusts were subjected perhaps, on this 

 account, to little more humid conditions than they would 

 probably have experienced if they were allowed to remain 

 free, out on the ground in nature. 



I later tried two more nymphs in my tests of this species. 

 They were both light ochre-colored individuals, and they were 

 placed under the same conditions for the experiment. Shortly 

 after moulting, the adults in both cases took on pigmentation, 

 which gave them the same general coloration as that exhibited 

 in the nymphs. They, also, gradually became noticeably darker 

 as time went on. After a month's interval they were decidedly 

 grayish, instead of yellow, and sprinkled with fine dark markings 

 over the whole upper surface of the body. In these experiments, 

 together with others that I have made, the evidence indicates 



