March, 1896.] 
Morse, Notes on Locust Stridulation. 
17 
These locusts belong to a group, the (Edipodinse, usually given 
subfamily rank, of which fifteen species are found in New England. One 
of the best known and most widely distributed of these in eastern North 
America is a species whose wings are black with a pale buff outer bor¬ 
der and with a few spots at the tip; this is the Carolina locust. It is 
very common on dusty roadsides and waste places in the latter part of 
summer and the early autumn. Owing to the prevailing tint of quiet * 
brown which clothes the majority of individuals they are known in some 
localities as “ Quakers.” 
Just how the rattling sound is produced is a matter of some specu¬ 
lation ; it is, however, entirely under the control of the insect, which 
can produce it or not at will. So far as recorded, only the male stridu- 
lates, though I suspect that the females of some species occasionally do 
in a less degree. Owing to the noise being produced in flight it is dif¬ 
ficult not only to observe the exact method of its production, but also 
to determine with certainty that it is confined to one sex. It is usually 
stated to be caused by the striking of the front edge of the wing against 
the under side of the wing-cover. This might occur as the result of an 
up-and-down blow or, as I venture to suggest, of a slight antero-poste¬ 
rior movement bringing the prominent veins of the under side of the 
wing-cover (humeral trunk and ulnar or anal veins) into collision with 
the raised veins of the base of the wing. 
Certain species, however, produce not only rattling, but distinct 
snapping sounds consisting of separate loud snaps or clacks, e. g., Cir- 
coteitix vernicu/atus, which often dances up and down in the air while 
doing so and not infrequently ends its powerful and erratic flight with 
a rattle immediately before alighting. It has seemed to me that the 
clacks may be produced in a different manner from the rattling sounds, 
and the following is suggested as a possible explanation. 
If the wing-cover of any of our larger (Edipodinse be examined 
there will be readily seen near its point of attachment, about in its mid¬ 
line, between the bases of two of the conspicuous veins (humeral trunk 
and anal) and pressing them apart, as it were, a distinct prominence. 
From this spring the two ulnar veins. If the wing-cover be inverted a 
depression will be found corresponding to the external prominence. 
In this depression lies the elevated base of the median vein of the wing 
when the wings and wing-covers are closed, and this arrangement holds 
these organs in place in the position of rest without any direct effort of 
the insect. If the wing-cover of a newly killed or relaxed GEdipodine 
be properly manipulated it will leave its place with a distinct snap, due 
