68 
of Southern species, as it is ef comparatively recent Southern origin 
and appears to die out from year to year in its more northern range. 
It was destructive in a single locality, the District of Columbia, late in 
the season, but was not reported by any of our numerous correspond- 
ents in spite of our inquiry. 
Of other Southern forms the green June beetle, Adlorhina nitida; 
imbricated-snout beetle, Epicerus imbricatus; squash-vine borer, 
Melittia satyriniformis, and American locust, Schistocerca americana, 
showed a perceptible increase in numbers, while the tobacco flea-beetle, 
Epitrix parvula was not so abundant. The larger corn stalk-borer, 
Diatrwa saccharalis, was not seen at all. 
The opportunity is taken to observe that the eggplant flea-beetle, 
Epitrix fuscula, a Southern form, was extremely abundant during the 
year, but flea-beetles, as the writer has had occasion to observe in his 
earlier article, seem to be little affected by changes in weather. 
In earlier mention of the weather in relation to the destructive green 
pea louse, Vectarophora destructor, and its abundance during 1899, the 
writer was unable to specify as to whether it belonged to the northern 
or southern group of injurious insects. It would now seem that it is 
a northern species, as it is recorded from several Transition localities, 
notably in Wisconsin and in Nova Scotia and other portions of Canada, 
where it is destructive, and, so far as reports go, it has not found its 
way farther south than a northern strip of the lower austral in south- 
eastern Virginia, near the seacoast, and a single known locality in North 
Carolina. It therefore falls naturally into the list of species that have 
multiplied in the neighborhood of the District of Columbia as a result 
of the cold winters experienced during two years. Nothing else can 
explain its great abundance, as none of its natural enemies, if we except 
the fungous disease to which it is subject and which has not yet been 
made the subject of special study by anyone, either in its relation to 
the multiplication of this insect or otherwise, have had any appreci- 
able effect in reducing the numbers of this pest. 
Taking into consideration the occurrence of this species throughout 
the country, it would appear that it was at least as numerous in 1900 
as in 1899, as during the latter season it was destructive over the same 
and additional area, although not in all cases to the same extent as in 
1899. Its increase westward was noticeable. 
ABUNDANT NORTHERN FORMS IN 1900. 
Of the northern forms of insects which were present in great num- 
bers in 1899 nearly all of the thirteen species mentioned (loc. cit., pp. 
56, 57) occurred in the same numbers during 1900, There were severe 
outbreaks of the oblique-banded leaf-roller, Cacwcia rosaceana, not 
only about Washington, but in various other portions of the country 
