GRASSHOPPERS IN GENERAL. 27 



thorax moves up and down ; soon the skin splits along the back from 

 top of the head to line crossing the base of front wings; the upheav- 

 ing action of the thoracic muscles continues until the body drops to 

 the ground, leaving the nymph skin clinging to the leaf ; the antennae 

 lie one on each side of the face and are thus drawn out from under the 

 body ; the wings come straight out of the pads as narrow, much- 

 wrinkled portions of cuticle. They are about five-eighths of an inch 

 long when the insect falls to the ground. Inside of an hour, depend- 

 ing upon the weather and time of day, the wings attain their full 

 length, one inch to one and one-quarter inches. The legs are not 

 brought into use in discarding this skin. Frequently the claws of the 

 old skeleton break away from their attachment and the insect falls to 

 the ground. This in no way interferes with the transformation. The 

 insect, when free from the old covering, though its limbs are quite 

 soft and unable to maintain its weight well, crawls to some secluded 

 place where it awaits the hardening of the bones and the expansion 

 of the wings. Before this is fully completed the insect begins eating 

 again. 



This change occurs more frequently in the morning, though I have 

 observed it at all hours from sunrise until five o'clock in the afternoon. 

 The complete change from beginning of molt until the insects are fully 

 developed occupies about one hour and a half on a bright, warm day. 

 Frequently I observed Sarcophagid and Tachinid flies flitting ner- 

 vously about the newly transformed insect. While I did not observe 

 one light upon the locust, it occurred to me that at this time parasitic 

 diptera might well place their eggs thereon. 



The first instances of the last molt observed were on July 6, and 

 from the number of adults then apparent I feel safe in saying that 

 none had reached the adult stage prior to July 1. At this time (July 

 1) adults of the Two-striped Locust, Melanoplus bivitattus, were com- 

 mon, and some of them were pairing. 



These notes were taken in the midst of nymphs in every state of 

 change, and frequently five or six were in view at one time. While 

 nearly all changed in July, there were some still changing as late as 

 September. 



DESCRIPTION OF PLATE IV. Various stages of the last molt of Melanoplus 

 differentials. 1, nymph just before the breaking of the skin along back of 

 thorax; 2, nymph beginning to come out; 3, mature insect dropping to the 

 ground; 4, cast-off skin, still clinging to the leaf; 5, grasshopper climbing up, 

 spreading wings to dry, and getting ready to eat; 6', fully developed grasshopper 

 on corn-stalk. 



