135 
Cal'optenus bivittatus also occasionally developes in considerable num¬ 
bers; it was very abundant in 1,877 over a limited area south of Platte 
river near its mouth. But these species feed chiefly on weeds, and 
hence are not often injurious except where they enter vegetable or 
flower gardens, especially the latter. 
Acridium americanum is occasionally quite numerous in certain locali¬ 
ties in the southern part of the State, especially in excessively dry 
years. I remember one season when they did considerable injuiy; 
they attacked the corn, but this was too old and hard to be injured 
much by them. They attacked the gardens, and ate the onions to ttie 
very roots; wheat was also injured by them. They have been also 
known to take wing and migrate several miles in little swarms. A 
day or two before flying they may be observed congregating on the 
bushes, high weeds, fences, etc., showing signs of uneasiness and 
restlessness. 
Warm, dry weather is favorable to the increase of locusts (grass¬ 
hoppers,—and in this sense only do we use the term “locust” in this 
article); it is in the excessively dry seasons that they have always 
been the most injurious. Not only are they then most numerous, but 
vegetation has then the hardest struggle for existence, and every green 
spot is sure to be overrun by these hungry pests. In the sections 
where fall wheat is grown, it is sure, as soon as it peeps from the 
dry ground, to suffer from their attacks. As a general rule, instead 
of spreading indiscriminately over the fields, they usually commence 
on one side, taking the wheat clean as they go, or nearly so; at least, 
this, is the usual habit of C. spretus and C. femur rub rum , the latter, as 
heretofore stated, being the most injurious of the Illinois species. 
REMEDIAL AGENCIES. 
Natural agencies which assist in keeping them in check .—Fortunate¬ 
ly, there are several natural agencies which have a tendency to pre- 
. vent their increase. Of these, we may mention the following as the 
most important: 
Climatic Influence .—Dampness is undoubtedly the most potent na¬ 
tural agent in keeping them in check. 
Although they may have hatched out in excessive numbers, yet if 
a rainy season follows soon afterwards, they will to a very large extent 
be destroyed, and the invigorated vegetation will bid defiance to the 
feeble attacks of those that remain alive. Like other insects their 
breathing apparatus consists of a series of tubes that permeate the 
body, connecting with opening or breathing pores along the sides of 
the body, one on each side of a segment; the moisture taken in by 
inspiration in all piobability produces disease, or at least in so ne 
way prevents the free passage of the air and thus lessens the vitality. 
Excessive changes during winter also appears to have a tendency t<> 
destroy the vitality of the eggs. That those of the red-legged and 
