298 
s 
From these records and the knowledge of allied species, I am 
enabled to present the following summary of the life-round of this 
insect. The parent fly makes a number of cuts about the twig of the 
Currant, two or three inches from the tip, girdling it and causing the 
tip to wither, die, and commonly break off, and deposits a single egg 
just below the cut. In the exceptional case noted above, of the egg 
being deposited in the severed portion, we have a case of mistaken 
instinet on the part of the female, either in depositing the egg above 
the cut or in cutting below the egg instead of above it, if the egg 
deposition is the preliminary step. The object of the girdling of the 
twig becomes apparent from a knowledge of the habits of European 
species and the other American species whose habits are known, and 
it is undoubtedly to cause a cessation of growth and the dying and 
drying condition of wood and pith, which best suits the needs of the 
developing larva. The young larva works slowly down the center of 
the twig, feeding on the pith and surrounding woody portion of the 
stem, becoming full-grown by autumn and spinning a delicate glisten- 
ing silken cocoon near the base of the burrow in which it winters as 
larva. The transformation to pupa and adult does not take place until 
early in May of the ensuing year, the mature insect then cutting its 
way out by means of its large and powerful mandibles. The specimens 
which we have from Mr. Allis emerged early in May, and the injury to 
the tips of twigs indicates that in New York also the adults are flying 
during this month. 
The very simple and easy remedy practiced by Mr. Rose is the best 
that can be suggested, and with thoroughness in its application will 
insure immunity from the borer. It will be advisable, however, to cut 
off the injured shoots at least two inches below the girdle rather than 
one, as the egg in some instances may have been deposited lower down, 
or the larva may have hatched and begun its downward course. 
The fact that this insect attacks a cultivated plant led to the suspi- 
cion that it might be of foreign origin, since it would not be at all dif- 
ficult to import its larva in currant bushes; but, although there are 
several closely allied European species having similar habits, none of 
these come anywhere near flaviventris in specific characters. The cul- 
tivation of the Currant in south Europe dates back but a few centu- 
ries, although it is a native of the north and temperate latitudes of 
both Europe, Asia and America. It is more than likely, therefore, in 
view of the abundance of the wild Currant throughout the northern 
half of this continent, and the absence or nondiscovery of the insect 
in Europe, that this currant-borer is limited for the present to the 
North American continent, having in later years transferred its atten- 
tion from the wild species to the cultivated varieties. 
Of the allied European species P. femoratus breeds in the lower 
twigs of the Oak, causing a spindle-shaped enlargement, often exteri- 
orly covered with minute, knob-like elevations, the injured portion 
