244 FAMILY VI. ACRIDIDJE. THE LOCUSTS. 



Later (1907, 9) he adds: "The flight of one of these locusts at- 

 tracts attention by its crepitating character; the conspicuous 

 wing-colors, red or yellow and black, in strong contrast, render its 

 flight easy to follow, and it is very frequently followed by others 

 of its kind, which drop to the ground in close proximity to it. 

 There can be no doubt in the mind of one who has watched these 

 actions repeated over and over, of the value of these colors as a 

 means of signalling, of attracting attention, and thereby effecting 

 or maintaining communication between the sexes or the individ- 

 uals of a community." 



Vosseler (1902, 10) has suggested that the bright hues of the 

 inner wings constitute a "contrast mimicry," enabling the owner 

 to dazzle or confuse any pursuer by suddenly closing them and 

 dropping quickly to the ground, where the dull colored tegrnina 

 blend so closely with the surroundings that the enemy searches in 

 vain for the brilliant object it was endeavoring to capture a mo- 

 ment before. As mentioned by both Hart and Somes, the Catocalse 

 among moths present a similar case of bicolored protective colora- 

 tion, having the outer wings dull gray or brown corresponding 

 to the hue of the tree bole on which they habitually rest, while 

 the inner ones are as brightly colored as that of any butterfly. 

 "When the moth alights, the gray outer wings instantly fold over 

 the bright inner ones, thus causing the insect to 'fade away' in 

 a bewildering manner." 



Since the flight of the Oedipodimp is almost always accom- 

 panied by a stridulation or crepitation, I believe that the theory 

 of Morse is much the more plausible, and that the bright colors are 

 for the keeping in (ouch one with another of the members of a 

 locust colony rather than to be used as a sort of camouflage to 

 dazzle their pursuers. Since the bright colored wings are posses- 

 sed by both sexes, they cannot be accounted for by the theory of 

 natural sexual selection, as might be the case were they present in 

 the males alone. 



The ground color of the inner wings and the hind tibia 1 often 

 varies much in the same species, shading from dull white through 

 yellow and orange to vermilion red, and, in the case of the tibia 1 , 

 sometimes to bine. The greater intensity of color is in part due 

 to age, and perhaps in part to the higher temperature of the lo- 

 cality where found, though other factors doubtless enter into its 

 cause. Brunei' (1893c) and Hart (1907, 214) have cited evidence 

 to show that a red coloration of wings and tibia"- 1 seems to be as- 

 sociated with that of a humid environment, while individuals or 



