.")() ANM'AL KKI'OKTs- OF DEPARTMENT OF AGlUOTJIfl T HE, 1940 
Ribes eradication now being used tei b large scale. Methods of pine 
tnanagemeni thai w ill result in the natural suppression of Ribi s in the 
fores 1 are under investigation by the Forest Service, and the Bureau 
of Entomology and Plan! Quarantine cooperates so far as facilities 
permit. 
CEREAL AND FORAGE INSECT INVESTIGATIONS 
GRASSHOPPERS 
The migration by flight of great swarms of the lesser migratory 
grasshopper were observed in detail for the firsi time during the 
summer of 1939. This migration originated in as area of about 
18,000 square miles in eastern Montana, where the infestation aver- 
aged about 50 grasshoppers to the square yard. Practically all of 
them Hew out of this area between June 20 and July 15, mostly in the 
direction of the prevailing wind, toward the northwest. The progress 
of these swarms was charted and their final termini located. Many 
swarms continued across the border into Alberta and Saskatchewan. 
Those that alighted in the United State- infested an area bounded by 
Blaine. Fergus. Judith Basin, Cascade. Teton, Pondera, and Toole 
Counties in north-central Montana. Egg laying began in that area 
about August I and continued until about September 15. 
A.s one of the results of extensive baiting experiments it was 
found that sodium fluosilicate as a substitute for the sodium arsenite 
poison generally used in the bait gave excellent results in concentra- 
tion- of 3 to 100 pounds of bran or other carrier. Sodium fluo- 
silicate bait kills grasshoppers more rapidly than do arsenical baits 
and yet is decidedly less dangerous to domestic animals. It would 
therefore be preferable to arsenical baits if it could be obtained readily 
in sufficient quantity at as low a cost. Field tests to determine the 
utility of baiting under fall conditions gave good results so far as 
kill was concerned. To be effective, however, such baiting must be 
done before egg laving begins. Experiments to determine the effec- 
tiveness of oil- and water-mixed baits distributed by airplane indi- 
cated the feasibility of this method and that baits mixed with bran 
and oil rather than bran and water might work best in airplane dis- 
tribution. The airplane baiting experiments also indicated the prac- 
ticability of using drier, lighter baits more suitable for economical and 
rapid spreading by plane, in quantities as low as 5 pounds per acre, 
under some conditions. 
MORMON CRICKET 
Observations <>n feeding habit- showed that the nymphs of the 
Mormon cricket fed most readily al air temperatures between 7t> and 
SO V., but that (hey fed at slightly lower temperature- than did the 
adults. It also appeared that whenever the temperature was high 
enough for activity and migration, they would feed on poisoned bait. 
The sp< ed of [nigral ion of nymphs was observed to be about LOO yards 
in 50 minutes, or a mile a day. 
A parasite generically new to science, belonging to the hymen- 
op terous family Encyrtidae, was reared from eggs collected in the Big 
Born Mountains of Wyoming. Some is Individuals emerged from 
b single cricket egg. The degree of parasitization of Mormon cricket 
i l' L r - by all parasites, however, averaged only 2.68 percent. 
