April, ’24J 
SMULYAN & WEBBER: UTETHEISA BELLA 
337 
ingly greater. Judging from chemical analyses and feeding tests that 
have been made in connection with previous experiments, the amount 
of arsenic contained on hay that has been sprayed twice at the rate of 
two pounds calcium arsenate per acre per application is so small that such 
hay may be fed to live stock with safety. 
Summary 
Contrasting conditions in southwestern Idaho with those in the 
eastern part of the state and in the weevil-infested portions of Colorado 
and Utah, it has been ascertained that instead of a rapid rise in the 
numbers of larvae following a somewhat definite “peak” in egg hatching, 
there was in 1923 a prolonged period of hatching and no definite peak. 
The “turning point of injury” occurred some fourteen days before the 
heavy emergence of larvae began to take place. Larvae were present 
in almost equal numbers for a period of three weeks. The highest 
point of larval population did not occur until 28 days after the “turning 
point of injury.” Under such conditions it has been determined that 
two sprays applied to the first crop of alfalfa are needed to afford 
protection from the alfalfa weevil. There are portions of the state 
where one spray is sufficient and there may be seasons where a second 
application will not be needed in southwestern Idaho, but the farmer 
must be prepared to use it if necessary. With the advance of the 
fanlfa weevil to still lower and warmer regions other adaptations of 
caotrol may be required. 
References 
(1) . U. S. D. A. Farmer’s Bulletin 741. 
(2) . Eleventh Annual Report Colorado State Entomologist. 
(3) . U. S. D. A. Farmer’s Bulletin 1185- 
OBSERVATIONS ON AN OUTBREAK OF UTETHEISA BELLA L. 
By M. T. Smulyan and R. T. Webber, TJ. S. Bureau of Entomology, 
Melrose Highlands , Mass. 
The destructiveness of certain species of insects when transplanted 
from their native habitats to completely new habitats and the destruc¬ 
tive activities in their native habitats of certain other species because of 
the modification of their environments (as through the introduction of 
new plants) is well known. The first category is well exemplified by 
such insects as the Gipsy Moth (Porthetria dispar L.) and the Japanese 
Beetle (Popillia japonica Newm.), the second by the Chinch-bug 
