448 FAMILY VI. ACRIDIDJE. THE LOCUSTS. 



the species generally called Caloptcnus bivittatus. The latter, 

 however, is an interior species while fcnwratus extends across 

 the continent." 



Rehn (1904d, 267) mentions Pequaming, Michigan, specimens 

 as ''having the posterior tibiae uniformly blood-red, varying slight- 

 ly in intensity, thus placing them in fenioratus. The form of the 

 cerci is also that figured by Scudder as typical fenwratus." He 

 adds: "Personally, I believe femoratns and bivittatus to be geo- 

 graphic forms of the same species very closely related but still 

 typical of each other over large areas." Now Scudder's figures 

 (1897, pi. XXIV, figs. 4 and 5) show very little difference in the 

 form of the cerci, and in the description of the cerci of bivittatus 

 (1897, 305) he says that they are "shaped almost precisely as in 

 M. fcHioratits, but more elongate and with the upper lobe of the 

 expanded extremity bent at a lesser angle with the basal portion." 

 It has already been shown that the form of the cerci in M. viri- 

 dipcs, M. keeleri and other species of Melanoplns varies exceed- 

 ingly and K. & H. (1905, 40; 1907, 297) reduced M. deletor to a 

 synonym under keeleri on account of the variability in the form of 

 that organ. One may pick at random 20 males of bivittatus from 

 any colony throughout its range, and no two of them will have 

 the cerci exactly alike and the extremes in form will be as great 

 or greater than described by Scudder. 



As to the two being geographic forms, that is controverted by 

 the known distribution, both forms being found together from 

 Ohio or farther east, to Oregon and Washington, and from Cen- 

 tral Canada to at least as far south as latitude 40. Scudder 

 says that typical birittatus does not occur along the Atlantic sea- 

 board nor along the Pacific coast south of Washington. It is 

 very probable that in these regions moisture and other conditions 

 of habitat are such that all the tibiae are red, just as in certain 

 localities the inner wings of Arphia j-anthoptcra are yellow and 

 in others orange-red. Numerous species of Melanopli and other 

 locusts, as ]\I. atlaiiis, confnsus, angustipennis, p<i<-]<<i>'<lii, etc., are 

 known with tibiae both red and otherwise colored, yet we do not 

 give varietal names to each of these. 



The entomologists of the East who, for the most part, have 

 seen only the red-legged form in the field, and have perhaps judged 

 bivittatus as distinct from a few specimens received in exchange, 

 should observe the two forms as they appear together by thou- 

 sands on a mid-summer day in the meadows and pastures of the 

 central West. They will then probably arrive at the same con- 

 clusion as has Somes, who says (1914, 9){) : 



