i8 University of Michigan 



the stridulation of a species is known to vary with changing 

 conditions of temperature, humidity, etc., on none of the occa- 

 sions on which notes were made on the stridulation of this 

 species did it resemble that of Cliortippiis curtipennis. The 

 closed caudal femur and tibia are held at a rather high angle 

 with the body and vibrated back and forth very rapidly 

 through a small arc, the resultant sound being a buzzing trill, 

 reminiscent of the notes of some species of Conocephalus ; 

 some of the individuals observed prefaced each trill with a 

 series of two to four brief clicks, still further increasing the 

 resemblance. The notes of some of the specimens observed 

 were approximately four seconds in length, separated by inter- 

 vals of from three to six seconds ; in other cases the notes were 

 only one or two seconds long, separated by variable intervals 

 up to five seconds in length. The coloration of this species is 

 nearly as variable as that of Chortippus curtipennis. 



Platybothrus brimneus (Thomas).--— Amidon, Aug. 21, 1920, 

 2 males, 2 females. 



Four specimens were taken in the course of an hour's col- 

 lecting on the flat mesa top of Black Butte, south of Amidon, 

 among the thin, very dry growth of grasses and other low 

 herbaceous plants. It occurred in company with Ageneoteftix 

 deorum, but was very much less common than that species. 



Stiraplcura decussata Scudder. — Devils Lake, July 8, 19 19, 

 I female. 



A single specimen of this species was collected by Miss 

 Olson. It was taken by sweeping the rather sparse growth 

 of grasses, liquorice, and other vegetation on the gravelly flats 

 on the north shore of Devils Lake. In spite of careful col- 

 lecting in the same vicinity for a period of several weeks the 

 following season, no more specimens were found. 



Agenedtettix deormn (Scudder). — Devils Lake, Aug. 12, 



