16 



Tlie Rocky Mountain Locust. 



third lobe] ; an oblique yellow line on each side of the body beneath 

 the wings; a row of dusky, brown spots along the middle of the 

 wing-covers ; and the hindmost shanks and feet blood-red, with 

 black spines. The wings are transparent, with a very pale green- 

 ish-yellow tint next to the body, and are netted with brown lines. 

 The hindmost thighs have two large spots on the upper side, and 

 the extremity black [more correctly three such spots, or, including 

 the extreme one at tip, four: Harris seems to have overlooked the 

 basal one]; but are red below, and yellow on the inside. The 

 appendages at the tip of the body in the male are of a long trian- 

 gular form. Length [to tip of abdomen] from 0.75 to 1 inch ; ex- 

 pansion of wings 1.25 to 1.75 inches." As this species, which is so 

 common, varies considerably, I have concluded to give Dr. Harris's 

 description without change, adding the following: Vertex but 

 slightly depressed, with a minute angular expansion in front of the 

 eyes; frontal costa usually but slightly sulcate ; sides parallel. 

 Eyes large and rather prominent. Elytra and wings generally a 

 little [usually extending about 1-6 their length beyond the abdomen] 

 longer than the abdomen. The cerci of the male rather broad and 

 flat [longer and narrower toward tip than in spretus] ; apex of last 

 ventral segment entire and truncate. The yellow stripes on the 

 side extend from the base of the wing to the insertion of the pos- 

 terior femora. The ground color varies with localities and age, and 

 most of the specimens from one or two sections appear to have un- 

 spotted elytra; sometimes a reddish-brown tint prevails; at others 

 a dark olive ; at others a dark purplish-brown ; .yet the markings 

 generally remain the same. 



Localities. — Maine, Massachusetts, Connecticut, New York, 

 Pennsylvania, Maryland, Tennessee, Illinois, Minnesota, Ohio, 

 Nebraska, Missouri, Kansas, Colorado, Wyoming, Vancouver's 

 Island (?), west coast of Americaf?). — [Thomas, Acrididw of N. A. 

 (1873), pp. 163-4. 



In addition to what Mr. Thomas states of the variation in color, 

 it may be added that the dark marks on the hind thighs are in ex- 

 ceptional specimens wholly wanting, and in others so confluent 

 that the whole of the upper part is brown-black. In order to show 

 how variable (within certain limits, however,) is the relative length 

 of wing, I have made measurements of over two hundred specimens, 

 all taken in St. Louis county, Mo. As the length of the abdomen 

 is an uncertain criterion, varying according as this last is distended 

 with eggs or contracted from one cause and another, I have made 

 these measurements from the juncture of the hind thighs and 

 shanks. The specimens were killed in the cyanide bottle, and 

 while yet fresh and supple laid flat on a scale divided into hun- 

 dredths of an inch. The furthermost hind leg was then stretched 

 until the suture between shank and thigh was just visible above the 

 inner border of the front wings. Careful measurements were then 



