41 
Eoswell, Mesilla Valley, and Carlsbad, N. Mex. Both the Col- 
orado and New Mexico localities are east of the Rocky Mountain 
range, and it appears to be only a matter of time when this species 
will succeed in invading the great sugar-beet regions of Nebraska; 
perhaps in time it will also travel farther eastward and become a pest 
in the Eastern States. It does not seem, however, that there is any 
immediate danger of general spread as in the case of the Colorado 
beetle; first, because the insect is a general feeder capable of thriving 
on plants belonging to several botanical orders, and hence does not 
need to migrate for food; and second, because the migration of the 
Colorado beetle is something almost unprecedented in entomological 
history; third, because according to present evidence the insect is 
Lower Austral and perhaps Tropical in origin, while the sugar beet 
grows best in the Upper Austral or Transition zones. From observa- 
tions of Professor Gillette it is obvious also that this insect, like the 
fall army worm, although it may invade the Upper Austral area, is 
not apt to survive severe winters; hence, if it becomes introduced very 
far northward its ravages will without doubt be sporadic and depend- 
ent upon the occurrence of winters sufficiently mild to favor its 
hibernation. 
PROBABLE METHOD OF SPREAD. 
As previously surmised, this species has doubtless come to our shores 
from Australia, India, or somewhere else in the Orient, possibly via 
the Sandwich Islands, and originally through the "Golden Gate," Los 
Angeles, or at some intermediate point on the California coast. If it 
was introduced in the northern portion of California, it drifted south- 
ward, as would any other species of semitropical or Lower Austral 
origin (which zones we conclude must have been the original home of 
the insect). From southern California its distribution eastward was a 
matter of easy accomplishment, by short flights of the moths aided by 
favoring winds through Arizona, possibly extreme northern Mexico, 
and New Mexico, where few high mountains barred its course, to Colo- 
rado, where, according to available data, its further spread appears to 
have ceased. 
In some respects this introduction has been accomplished in what we 
may surmise was the manner of establishment of certain other injur- 
ious insects, examples of which are the potato tuber worm {Gelechia 
opereulella) and perhaps the imported cabbage web-worm {Ilelhda 
undalis), both of which inhabit California. They probably originated 
in the Orient, and evidently followed a similar course, with this differ- 
ence, however, that as one feeds in the tubers of potatoes and the other 
in the heads of cabbage, and both are small species, it is more likely 
that the}^ were introduced in part by " commercial jumps," which 
accounts for their being found farther east throughout the South. Both 
