Characters of the Species. 



15 



[Fig. 



of wing, and the structure of the terminal joint of the 

 male abdomen, which is turned up like the prow of a 

 ship — this last character being the 

 most important 

 and constant. 

 TheRockyMoun- 

 tain species has 

 the wings ex- 



Kockt Mountain Lo- , ° Red-legged Locust :— 



oust -—Anal characters of tending, when Anal characters of male ; 



male; a, side view; b, c, hind a, side view ; 6, c, hind and 



and top views, of tip. closed, about top views, of tip. 



one-third their length beyond the tip of the abdomen 

 (Fig. 2), and the last or upturned joint of the abdomen 

 narrowing like the prow of a canoe, and notched or pro- 

 duced into two tubercles at top (Fig. 3). The wings of 

 the Red-legged Locust extend, on a average, about one- 

 sixth their length beyond the tip of the abdomen (Fig. 1), 

 and the last abdominal joint is shorter, broader, more 

 squarely cut off at top, without terminal tubercles, and 

 looks more like the stern of a barge (Fig. 4). 



descriptive: detailed comparisons with the red- 

 legged LOCUST. 



A large amount of material examined, has enabled me to make 

 very thorough comparisons between the two species. The genus 

 Caloptenus to which the species belongs, is distinguished principally 

 by the stoutness of the spine-like tubercle on the fore-breast be- 

 tween the front legs, and by the tip of the abdomen in the male 

 being much swollen. Mr. Cyrus Thomas, in his admirable work on 

 the "Acrididaeof N. A.," has published good descriptions of the 

 known N. A. species, and I will transfer what he has said of the 

 two in question — adding only some subsidiary remarks in brackets, 

 and at the close : 



Caloptenus Femur-rubrum, Burm. Handb. Ent. , II, 638. 

 Syn. Acridium femur-rubrum, Deg. Ins. Ill, PI. 42, Fig. 5, p. 498. 



« femorale, Oliv., Encyl. Meth., 121 Ina. VI, 228. 

 Gryllus (Locusta) erythropus, Gmel., Linn. Syst. Nat. I, IV, 2086. 

 "Grizzled with dirty olive and brown; a black spot extending 

 from the eyes along the sides of the thorax ; [but never upon the 



