Occasional Papers of the Museum of Zoology 33 



and in dry, grassy pastures where there were considerable 

 areas of bare soil exposed. Although fairly common in this 

 vicinity, it was much less numerous and more local in occur- 

 rence than Circotettix rabiila, with which it was usually found 

 in company. 



A. carliniamis stridulates on the wing in a somewhat similar 

 manner to the species of Circotettix. The sound produced is 

 a loud, whirring noise, very different and very much less start- 

 hng than the crackling of its companion C. rabiila. While the 

 sound is being produced the insects will hover in the air, often 

 practically motionless, or moving slowly along, and rising and 

 falling gently. They sometimes remain in the air stridulating 

 for periods of a minute or more. This species is extremely 

 alert and wary on bright, sunny days, but specimens are rather 

 easily captured in cloudy w^eather. 



Circotettix rahula Rehn and Hebard (showing tendencies 

 toward race nigrafasciatus Beamer).-° — Medora, July 30- Aug. 

 3, 1920, 4 males, 9 females; Amidon, Aug. 21-25, 1920, 14 

 males, 10 females. 



This species was common in the southwestern part of North 

 Dakota wherever exposures of bare, dry soil were found. It 

 was common in the more sparsely vegetated areas on the dry, 

 grassy uplands, in company with Aerochorcutcs carlinianus, 

 but more numerous than that species. In the region about 

 Amidon it was found in large numbers on the rocky slopes 

 and top of Black Butte and on the nearly bare clay slopes 

 in the 'breaks" of the Bad Lands. This species was by far 

 the noisiest grasshopper found in the state, its loud, crackling 

 stridulation being audible for a quarter of a mile or more on 

 a still day. 



-" Circottcttix rabula Rehn and Hebard (= Cicoteftix undulatus of 

 most authors). 



