98 TO E.vro: 



ber of these is of use in dtstinguishir uul the ; 



pine in the outer ro\ r impor- 



; )ines tl. ;our articulated spurs, which 



in two pairs, one on the outer and one on the inner 

 of the tibia. The ;i>hed. In the 



males the ventral surface of the abdomen consists of nine se 

 while in the ire but eight. The caudal end of the 



body in the females is furnished with four horny app^ the 



or; in the male the ventral pair of appenda^ . pre- 



-ingle pL 



With many species of the Acrididae we find the males furnished with strid- 

 ulating organs. These are nol nearly so highly developed as those of mem- 

 bers of the two higher families, and are used only in the day-time. The 

 Locusts stridulate in two \\> :ain species rub the inner surface of 



hind legs against the outer surface of the wing-covers. With the- 

 there is a thickening of one of the main longitudinal veins in the centre of the 

 wing-cov- and a remarkable extension of the two area- 



tween this vein and the costal margin of the wing cover (area scapuldris and 



. which serves as a sounding-board, and which is wantir. . 



the female. The most common representatives of the insects which stridulate 

 in t: .long to the gen According to Scudder, the 



Stenobothri, when about to stridulate, place themselves in a nearly horizontal 

 position, with the head a little elevated; then they raise both hin 

 once, an' -he femora against the outer surface of the tegmina, pro- 



notes which in the different species vary in rapidity, number, anddi: The 



one or two movements are frequently noiseless or faint : and when the 

 iie movements are less rapid. Scudder has recorded the 



v means of a musical notation.* 

 The second method of stridulation practised by locusts is by rubbing 



:her the upper surface of the front edge of tru nd the under 



face of th Those which employ this method stridulate du 



Several common species per o the CEdipodinas will 



rtain other clo '. species produce no sound whatr 



Locusts lay the- 1 with a tough glutin- 



in the ground, the 



positor of the fema' d for making the n 



. The ' the four hor vhich it is com- 



d can be alt , applied togctlv read apart: in 



tter to force 1 of 



the abdomen into the ground. 1 ts the Rocky Moun- 



* Proc. Bost. Sc ,1. XI. 



