218 



in Nebraska specimens. Gillette states ('04) that the species 

 occurs both on hills and on level ground in Colorado, and of his 

 specimens 69 had red and 58 blue tibiae. McNeill ('99) found 

 the tibiae green in southwest Arkansas, red and green in Newton 

 Co., and purplish red in Marion Co. The records of this species 

 indicate that the cooler northern climate has the same effect 

 as a humid climate in favoring the development of red tibiae. 



The Rocky Mountain locust, M. spretus, has red tibiae, and 

 its normal range is from the Saskatchewan towards Colorado and 

 Utah. Examples with pale blue tibiae (M. spretus coeruleipes 

 Ckll.) are recorded from Nebraska by Dodge ('78). 



Finally, Scudder has separated M. bivittatus, having yellow 

 tibiae, from femoratus, having red tibiae, but these are almost 

 certainly varieties of one species. Femoratus ranges from Nova 

 Scotia and Maine to British Columbia and California, and south 

 to Colorado, Nebraska, Missouri, Illinois, Indiana, Maryland- 

 and North Carolina. It is much the commoner of the two in 

 Illinois, all but 4 out of 133 taken by us in this state being of 

 this variety. Bivittatus abounds on the Great Plains, ranging 

 principally from Texas to Utah and Nebraska and, in lesser 

 numbers, from Texas to Ohio, and northward into Canada be- 

 tween Manitoba and the Pacific. The range of these two spe- 

 cies accords with that of the two tibial color-varieties of species 

 previously mentioned, indicating that variation in tibial color, 

 which is the only constant difference noted between bivittatus 

 and femoratus, is not a sufficient basis for specific separation. 



Briefly, then, some species of Mela nop! us have bluish tibiae 

 only, some red only, regardless of locality, but in other species 

 we find individuals with both kinds of tibial coloration in vary- 

 ing proportions, red on the one hand, and various combina- 

 tions of blue, green, and yellow on the other, the proportion of 

 the two differing greatly according to species and also accord- 

 ing to locality, in all species but possibly one the blue tibiae 

 increasing with the increase in aridity or in sandiness, except in 

 higher latitudes, and being most numerous east of the Rocky 

 Mountains, from Texas to Nebraska, and least so east of the 

 Mississippi and towards the extreme north. 



