March, iSo6.] MORSE, NOTES ON LoCUST StRIDULATION. 19 



they had evidently but just become sufficiently warmed by the morning 

 sun to take an active part in life, and in consequence allowed a closer 

 approach than is the usual custom of this wary species. Two of them 

 seemed more wide awake than the others, and as they crawled about 

 would occasionally stop, slightly elevate the hinder part of the body 

 and rapidly move the hind thighs up and down against the wing-covers, 

 producing a distant " scritching " sound clearly audible at a distance 

 of three or four feet. This act was repeated several times at intervals of 

 a few seconds. No females were seen near by. 



Desiring to make further observations on this mode of stridulation 

 in the CEdipodinae I secured one day after my return several examples 

 of Encoptolophus sordidus and Arphia xanthoptera and enclosed them, 

 together with some grass, in a pasteboard box of about a cubic foot ca- 

 pacity, covered it with netting and placed it in the sun. Both sexes of 

 both species were represented, but of females there were but two of each. 



At first their efforts were entirely in the direction of escape, but after 

 a short time they became more quiet and were left by themselves, an 

 occasional approach being made to see how matters stood. Nothing of 

 interest was learned from the Arphias, but after some time two males of 

 E. sordidus, oblivious to their surroundings, became attentive to one of 

 the females. Aroused by her near presence they crawled rapidly about, 

 and as they approached her would stop, stridulate for a second with 

 their hind thighs, and excitedly leap toward or upon her, when, being 

 repulsed, they would repeat the operation. The sound produced was a 

 very high-pitched " I'chT-i'chi-T'chT-i'chi. " 



Another sound of an entirely different character was made by them 

 in a different manner. The hind thighs, instead of being closely ap- 

 plied to the wing-covers, were spread somewhat apart and violently 

 vibrated, moving, as nearly as could be judged, up and down with ex- 

 treme rapidity and striking as they did so upon the bottom of the box. 

 The sound produced was a peculiar ''r-r-r-rd" or "r-r-r-rt," low in 

 tone and of considerable volume, leading me to think from its quality 

 that it was due in part to the vibration of the pasteboard bottom. Once 

 it seemed as if the wing-covers took some part in it, vibrating laterally ; 

 but as the act was witnessed but twice, both times from the side, and 

 was too rapid for the e3^e to follow, I am uncertain of the exact method 

 of its production. 



Lack of time in suitable weather prevented further observations, 

 but these are reported in the hope of bringing out information on the 

 subject and inducing other observers to pay some attention to this in- 

 teresting habit. 



