MORSE: ORTHOPTERA OF NEW ENGLAND. 239 
tegmina to a high angle with the body, adjusts them at an angle 
with each other in position to bring the scraper to bear on the 
file, and sounds his call. 
Second Method. — -If the hind thigh of a male of almost any 
of our Acridine (Tryxaline) Locusts (except Mecostethus) be ex- 
amined, there will be noticed on the basal half of the inner side 
a prominent ridge and projecting from it a row of very fine, 
short, erect, peg-like teeth, developed, it is probable, from mod- 
ified hairs. These are usually more thickly set toward the base 
of the femur, and sometimes are scatteringly placed toward the 
end of the row. They vary much in number with the species, 
sometimes forming a long, close-set series as in Pseudopomala, 
sometimes a short and irregular one. They are present in the 
female of Chloealtis conspersa in a less developed condition, — 
at least in some individuals. 
When the femora are raised vertically and at the same time 
pressed inward, these teeth rub against certain prominent veins 
of the wing-covers and cause them to vibrate, producing a faint 
scritching sound, sometimes loud enough to be heard at a dis- 
tance of several feet. In Mecostethus and most Oedipodinae 
these peg-like teeth are absent from the hind femora but their 
place is taken by tooth-like prominences borne on the tegminal 
veins, especially on one (mediastinal) which is undeveloped in 
most of the Tryxaline series of Locusts. The call of Mecostethus 
gracilis, in which they are exceptionally well developed, is audible 
at a distance of fifty feet or more. 
Third Method. — In addition to the foregoing, the Oedipodinae 
usually have the ability to make distinct crepitating, rattling, 
or even snapping sounds during flight. Just how these are pro- 
duced is perhaps open to question. They are generally said to 
be due to rapid blows on the tegmina by the stiff front margin of 
the wings. Several possibilities have been suggested and it 
still remains for some ingenious person to determine the exact 
procedure. So loud is the noise produced in this way by some 
species in the Far West that it may be heard at a distance of a 
quarter of a mile. The Broad-winged or Snapping Locust, the 
most skilled in this method of any New England species, is able 
to sound either a continuous rattle or separate loud snaps or 
clacks at will, while in flight or during airy evolutions given in 
