24 INSECTS INJURIOUS IN 1902. 
gallons probably would have been all that was necessary. Every 
farmer in districts likely to be affected should have a hopper-dozer 
ready for use in the spring and not postpone the making of one 
until the pest is upon him and every one, including himself, is too 
busy to stop for the work. These machines can be used until the 
grain is fully one foot high without injuring it. They cost all 
the way from $4 to $16, depending upon the size, the weight of 
the iron and the cupidity of the firm making it. It should be borne 
in mind that as useful as the hopper-dozers are, they should be re- 
garded in the light of a make shift for use in an emergency, since 
fall plowing when properly done by all farmers in a neighborhood 
is a sure method of extermination. 
Fig. 17 shows a model of a new kind of hopper-dozer in- 
vented by a Minnesotan. The driver sits behind at end of the 

Fig. 18. — Melanoplus Fig. 19. — Melanoplus Fig 20. — Melanoplus 
spretus; dorsal view atlanis; dorsal view femur-rubrum ; dorsal 
of end of male abdo- of end of male abdo- view of end of male 
men. men. abdomen. 
pole and two horses push the machine ahead of them. A strong 
fan blows the young hoppers against the bottom of rollers which 
crush them, the rollers being cleaned automatically. 
There are times when the hopper-dozer can be used to better 
advantage than at others. A cold raw day, for instance, does not 
offer favorable conditions. Again, when hoppers are completely 
winged and fly a long distance when disturbed which, by the way, 
is after most of the injury has been done, dozers are of practically 
no use. It was to farmers owning hopper-dozers that oil was fur- 
nished free by the Entomologist, each farmer applying to his 
county commissioner for an order for oil on a local dealer. The. 
price of oil ranged all the way from 9 cents per gallon including 
the barrel at Minneapolis to 11.1-3 cts. at Perham without con- 
tainer ; 1434 cents in barrel lots with barrel at the Standard Oil 
Co.’s Warehouse in Crookston; 15 cents at Gentilly; 14 and 15 
