ORIGIN OF THE WINGS IN LOCUSTS, BUGS, ETC. 141 



the creased wings in the pupa of butterflies is exactly like that of cockroaches 

 and bugs. The difference is only that the folds of integument furnishing the 

 wings with an ample store of material for their construction reach in a relatively 

 shorter time, that is the space of time between two moults, the same extent that 

 they would otherwise attain only in the course of several periods of growth in 

 the ametabolous insects. 



Ignorant of Graber's paper, we had arrived at the same result, 

 after an examination of the early nymph-stages of the cockroach, as 

 well as the locusts, Termites, and various Hemiptera. In all these 

 forms it is plainly to be seen that the wings are simply expansions, 



FIG. 156. Nymph of Aphrophora permutata, with enlarged view of the wings and the veins : 

 pro, pronotum ; c, mesoscutum ; lab, 1st abdominal segment. 



either horizontal or partly vertical (where, as in locusts, etc., the 

 body is compressed, and the meso- and metanota are rounded down- 

 wards), of the hinder and outer edge of the meso- and metanotum. 

 As will be seen by reference to the accompanying figures, the wings 

 are notal (tergal) outgrowths from the dorsal arch of the two hinder 

 segments of the thorax. At first, as seen in the young pupal cock- 

 roach (Fig. 152) and locust (Fig. 153, also Figs. 154 and 156) the rudi- 

 ments of the wings are continuous with the notum. Late in nymphal 

 life a suture and a hinge-joint appear at the base of the wing, and 

 thus there is some movement of the wing upon the notum ; finally, 

 the tracheae are well developed in the wings, and numerous small 

 sclerites are differentiated at the base of the wing, to which the 



