29 
Miscellaneous caperiments.—The habit of the differential to remain 
along sloughs, ditch banks, etc., suggested the scattering of lime, 
acid phosphate, kainit, and other substances to check the march of 
the grasshoppers out into the crops; but, as none of these materials 
proved of any value, a continuation of this line of work was early 
abandoned. 
We found it advisable not to destroy cockleburs growing in the 
vicinity of the egg areas, as this plant is the favorite food of young 
grasshoppers and serves to congregate them, which not only renders 
more available effective remedies, but also preserves the stand of corn 
and cotton in these localities. Where it is possible, we also recom- 
mend delaying the cutting out of the crops to a stand until the young 
hoppers have been destroyed by some or all of the remedies stated 
above. 
NATURAL ENEMIES. 
Aside from the very timely rainfall during the latter part of May 
and in June, there were many predatory and parasitic enemies found 
common to the differential locust in the Mississippi Delta. 
Fic. 6.—Trombidium locustarum: a, female with her batch of eggs (from Emerton); b, newly hatched 
larva—natural size indicated by the dot within the circle; ¢, egg; d, e, vacated eggshells (from 
Riley). 
Upon the eggs.—Three predatory and two parasitic forms were 
found feeding to a greater or less extent upon the eggs. 
The locust mite, Zrombidium locustarum (see figs. 6 and 7), which 
occurs throughout the United States and Canada was in evidence in 
the Mississippi Delta. The full-grown mites, as well as bunches of 
the small red-colored eggs, were commonly seen during the cultivation 
of the land in April and May. While most abundant in the vicinity 
of the egg-heds, it was not uncommon to find them anywhere over the 
entire plantation. Many were placed in breeding cages where quan- 
tities of eggs of differentialis and of other species were kept, but 
we were dic ponred somewhat in not finding them more ravenous 
feeders upon grasshopper eggs. From the statements of other obsery- 
