— 9 — 



Winter spea'/iiens.— As cold weather approaches in tall, the 

 bright contrasts of color in our locust gradually disappear, and 

 the insect takes on or assumes a dull-reddish tinge throughout. 

 The brown bands on top and sides of prothorax and face 

 become almost obliterated, and the white bands in middle 

 of sides and on lower edge of pronotum entirely disappear. The 

 hind wings change to a beautiful rose color which is quite 

 decided on the basal half, and which gives the insect quite a 

 different appearance while flying from that which it presented 

 under like circumstances when it first became a voladora 

 and for at least two months thereafter. 



The colder and longer the winter the deeper appears to 

 become the reddish tinge in the hibernating insects. Some few 

 show a dull smoky-brown, while others become almost dirty 

 black in their general color. In all, however, the wings are more 

 or less vividly rose-colored. 



Spring specimens.— In spring, when the insects forsake their 

 winter-quarters and begin to feed upon the fresh vegetation 

 and the time for mating approaches, the reddish hue of winter 

 gradually gives way to a lighter shade. The rose color on the 

 wings slowly disappears and in time is lost altogether. By the 

 time egg-laying begins the insects have assumed a yellowish- 

 olive hue where in Avinter they were red, and the wings instead 

 of being rosy are yellowish hyaline. 



When the wings are transparent the basal veins and cross- 

 veins are white, as they change to rose-color the veins also 

 assume that hue, and when they lose the rose-color and 

 become hyaline the veins change to yellowish. 



Thus we find that the same insect exhibits three distinct 

 color-variations during its life as a voladora. .Similar color- 

 variations have been reported in the Old World peregrina as 

 seen in different regions at times visited by it. But we do not 

 recall any record of an attempt at an explanation for these 

 variations in that insect. Similar, but less decided, variations in 

 color have been observed by us in wintering locusts in North 

 America. In fact, most of the brown or yellowish-brown locusts 

 become more or less tinged with red late in fall after they 

 have been several times exposed to frosts. 



By observing the general color of the locusts making up an 

 invading manga, it is possible, therefore, to tell whether they 

 are 3'oung, middle-aged or old. None of the quite red specimens 

 that were dissected b}' us here at headquarters contained fully 



