6 
beetles on Lake Erie in 1870 on various floating objects, and the 
writer in subsequent years saw the borders of the same lake lined for 
a foot and more with the hordes of these beetles that had been blown 
into the water and had then been cast up on the shore. 
Beginning with about 1880, it will be noticed, the Colorado beetle 
appeared in many potato fields of the Gulf region and elsewhere in 
the South. In certain localities, particularly in Alabama (where it 
was quite injurious for a time) and South Carolina, this insect seems 
to have disappeared, and httle danger of continuous injury need be 
anticipated there, as invasions of extreme Lower Austral territory 
have thus far been merely sporadic appearances. Still, whenever 
atmospheric conditions favor, the species does temporary damage in 
such places, only to be killed down again for a number of years, after 
which the beetles reappear, sometimes invading new localities. It 
thus will be seen that it would be a somewhat difficult task to outline 
definitely the permanent distribution of this insect. It is nearly 
limited, however, as regards severe injuries to the country east of 
the Rocky Mountains, extending from the Lower Austral to the 
Transition life zone, and is likely any year to be injurious in extreme 
portions of this area. 
Injuries by this species in the potato section of Aroostook County 
in northern Maine are well known, and the region there, as well as are 
portions of Colorado, is credited to the Boreal life zone.*| From recent 
reports it is fair to say that the species is scarcely a pest at the pres- 
ent day in its original habitat nor in neighboring States, since during 
the last five years no reports of extensive injuries have been received 
from Colorado, Kansas,’ Nebraska, or South Dakota. It appears to 
be firmly established, however, in the States just west of the Missis- 
sippl River and from there eastward to Nova Scotia and New Bruns- 
wick and southward to the northern portions of the Gulf States. 
DISTRIBUTION LIMITED BY EXTREMES OF TEMPERATURE. 
Some of the conditions which prevent the too rapid multiplication 
and permanent establishment of the potato beetle are known. At St. 
Louis, Mo., is was noticed by Riley that during very hot, dry weather, 
as in 1868, this insect failed to go through its transformations in the 
ground, the latter becoming so hot and baked that the pup dried 
out, and the beetle, if it succeeded in throwing off the pupal skin, 
failed to make its way to the surface. It was also noticed that the 
larvee frequently perished under the broiling sun when the ther- 
«These regions may in time be recognized as lying within the Transition zone. 
6 Report from Mr. Warren Knaus, dated May 18, 1907, states that this insect 
has appeared in great numbers in Kansas and threatens serious damage to young 
crops. 
[Cir. 87] 
