﻿OP THE STATE ENTOMOLOGIST. 



125- 



Ked-legged LocnsT. 



EASILY CONFOUNDED WITH THE EED-LEGGED LOCUST. 



In my endeavors to accurately map out the territory in our State 

 invaded in 1874 by the Rocky Mountain Locust, I have been fre- 

 quently puzzled by accounts from counties east of the limit-line 

 presently indicated. In every such instance, where I have been able to 

 obtain specimens, they proved to be the common Red-legged Locust. 

 t^is 26] This last species is common in most of the 



States, extending to the Atlantic, and is 

 even reported in parts of the Rocky 

 Mountain region, where the Migratory spe- 

 cies is at home. The two bear such a 

 close general resemblance that even entomologists have doubted their 

 specific distinctness ; and indeed size and colorational characters 

 would not suffice to separate the exceptional individuals which depart 

 most from the typical characters of their species, and approach most 

 [Fig. 27 ] to those of the other. Yet they are dis- 



tinct, as species go, and in order to prop- 

 erly study the distribution of the Rocky 

 Mountain species, and its power of be- 

 coming acclimated in the Mississippi 

 Valley or not, it is of the first importance that observers confound not 

 the two species. Hence, I shall describe in detail the two insects. 

 From these details, which follow, it is evident that the distinguishing 

 [Fig. 28] . characters, most easily observed 



by the non-entomologist, are the 

 relative length of wing, and the 

 structure of the terminal joint 



^ ., f , , , . , . Red-legged Locust: 



01 the male abdomen, which is Analchaiaciersotmale; 



Rocky Mountain Lo- . i ti ^i ^ i • «. side view; 6, c, hind 



cust:— Anal characters of turned Up like the prOW Of a ship and top views, of tip. 

 male; a, side view; b, c, 



hind smd top views, of tip. — this last character being the most important and 

 constant. The Rocky Mountain species has the wings extending, when 

 closed, about one-third their length beyond the tip of the abdomen, 

 and the last or upturned joint of the abdomen narrowing like the 

 prow of a canoe, and notched or produced into two tubercles at top. 

 The wings of the Red-legged Locust extend, on an average, about one- 

 sixth their length beyond the tip of the abdomen, and the last abdom- 

 inal joint is shorter, broader, more squarely cut off at top, without 

 terminal tubercles, and looking more like the stern of a barge. 



Rocky Mountain Locust. 



