GEOLOGICAL SUEVEY OF THE TEKEITOEIES. 723 



bluisli cast is very evanescent, almost wholly disappearing from a speci- 

 men kept for ten hours, though not immersed in any liquid. The exter- 

 nal face of the posterior femora is crossed by three oblique dark and 

 two intermediate white bands; the dark bands cross over to the upper 

 margin of the inner face ; inner face and under side yellow. The pos- 

 terior tibiae pale greenish blue, generally with a dark ring near the base ; 

 spines black. Tarsi dark above, white beneath. Abdomen dark, mot- 

 tled above; the posterior margins of the segments bluish white; venter 

 yellowish white. 

 Length about .8 or .9 of an inch. July 5-11. 



G. Mvittatus, Say. 



This species is very variable, both in color and size, yet it is easily re- 

 cognized in almost any of its numerous variations, and it is only the 

 more particular investigation that causes the entomologist to doubt the 

 identity. I herewith give some notes in regard to the varieties met 

 with the past summer in the Northwest. 



OmaJia, August 1. — Female, living specimen. Stripes on the pronotum 

 very distinct, rather broad, reddish yellow, the intermediate space a 

 velvety black, (or dark fuscous.) The general color of the sides of the 

 insect, a purplish red ; the face, and the external face of the posterior 

 femora, the same color ; the upper, external carina of the ijosterior fem- 

 ora, shining black ; posterior tibiae deep blue, fading at the apex to pale 

 rufous ; tarsi rufous. Elytra slaty brown, with a few dusky spots near 

 the base on the disk. Wings transparent, but tinged with red ; nerves 

 and nervules along the front margin dusky ; rest colorless. The pos- 

 terior femora have two black spots on the upper margin of the internal 

 face; the spines of the posterior tibiae, black. These specimens were 

 found abundant on a tall weed much like hemp, in company with G. dif- 

 ferentialis and Acridium emarcjinatum. In some specimens the dark 

 stripe along the posterior femora occupies the upper half of the disk ; 

 then there is above this a yellow line, between the upioer lateral and 

 dorsal carinae, and then a dark stripe along the upper margin of the in- 

 ner face. The general color is sometimes a dark ashy green, which 

 prevails on the head, sides, and beneath. The cerci of the males are 

 broad, extending back a short distance, then bend suddenly upward, 

 leaving a rounded protrusion on the lower edge. Sub-anal plate obtuse 

 and entire at the tip. 



In Platte bottoms I noticed quite a number of individuals of this spe- 

 cies in the long rank grass, with the general color a bright yellow, 

 while others were ashy green, yet the two varieties were frequently 

 seen pairing. This yellow variety was also seen at Sioux Falls, Da- 

 kota, August 25. 



G. differ entialis, Thos. 



The individuals of this species found at Omaha, August 1, in com- 

 pany with the previous species, had the antennae red ; general color of 

 the head and thorax, pale olive ; abdomen and pectus, bright yellow. 



Dimensions. — $ Length, 1.2 inches ; elytra, 1 inch ; ijosterior fermora, 

 .63 inch; posterior tibiae, .58 inch; pronotum, .24 to .26 inch. 



At North Platte I noticed quite a number of the dark variety of this 

 species, with bright yellow stripes. This variety has the posterior fem- 

 ora marked with black bands, and the general color is quite dark, al- 

 most a black. These were found congregated on a large weed growing 

 I^rofusely in the Platte bottoms, and were often seen pairing with other 

 varieties. 



