
adeeb ras 
that, except for slight recessions on the fourth and sixth weeks, the per- 
centage of mortality steadily rises for at least nine weeks after the 
bait is applied. This is probably due chiefly to the fact that the liv— 
ing earwigs eat the poisoned dead. The six blocks which were kept under 
observation for a period of nine weeks had an earwig population of 41,696 
at the beginning of the experiments and a population of 1,168 at the end 
of 9 weeks. These results seem to indicate that a city block forms a 
rather isolated unit which is not heavily invaded by earwigs from sur-— 
rounding infested areas." 
Mr. Crumb also reports that the Puyallup laboratory "prepared an 
exhibit. and had charge of a booth dealing with the earwig at the Western 
Washington Fair. A member of the laboratory staff was constantly in at- 
tendance at this booth during the 7 days the fair ran. The number of per- 
sons who actually examined the exhibit was 6,138." 
During the first part of September K. B. McKinney, of the Tempe, 
Ariz., laboratory, spent a few days in a general survey of the higher 
altitudes in the vicinity of Payson, Ariz., to determine at what alti- 
tudes the tobacco stalk borer might be found. He says: "The borers 
were found infesting Datura sp. at an elevation of a little above 6,000 
feet. These plants were not heavily infested but both larvae and adults 
were found. A light infestation was also found in a few experimental 
tobacco plants at about 5,000 feet elevation." 
N. F. Howard, Columbus, Ohio, reports the liberation, in the States 
of Alabama, Georgia, Kentucky, New Jersey, New Mexico, Ohio, and Virginia, 
during the months of August and September, of 10,531 Paradexodes epilach— 
nae Ald., the tachinid parasite of the Mexican bean beetle. These liber- 
ations consisted of colonies varying from 125 to 1,300 flies. In view 
of the great difficulties which have been experienced in the efforts to 
introduce and establish this parasite, it is of interest that "Recoveries 
of P. epilachnae have been made at Columbus, Ohio, in numbers during the 
past month. On September 30, parasitized larvae were recovered from two 
locations more than a mile from the place of liberation. These locations 
were to the west of the place of liberation and in the direction of the 
prevailing winds." 
In connection with his local studies of the beet leaf hopper, 
H. E. Wallace, Riverside, Calif., reports a marked variability in the vir-— 
ulence of the curly-top disease of sugar beets as transmitted by the leaf 
hoppers coming in from their natural breeding areas. The interesting 
point is the close relationship in such variation with human and other an- 
imal diseases. It is possible to rear, under controls, leaf hoppers free 
from this disease, and experimental work is reported indicating that such 
nonviruliferous stock, if impregnated by being placed on plants with a 
mild type of disease, conveys such mild type, and if placed. on plants 
with a virulent type, that type is transmitted. These experiments have 
been conducted in close cooperation with phytopathologists of the Bureau 
of Plant Industry. A practical application of this information is not 
in sight. Clearly the type of disease carried by the migrating leaf 
hoppers is governed by chance, and control of these leaf hoppers in 
natural breeding grounds is still problematical. 
