388 
delicate egg was found embedded in the very heart of the pith (Fig. 42 b). 
It is elongate-oval, about a millimeter in length, whitish in color, deli- 
cate, and without any characteristic sculpturing (Fig. 42 d). 
At the suggestion of the writer a large number of the severed twigs 
were marked by Mr. Treat, with the idea of following up the subsequent 
development of the insect. These were examined from time to time, 
and on the 5th of October a large number of marked twigs were sent 
to this office, and it was found that in every instance the eggs had failed 
to develop, and the twig had merely died back from the point of exci- 
FlG. 42. — Phylloecus flaviventris : a, egg puncture; 6, same in section showing egg in pith — enlarged ; 
e, severing of terminal by female; d, egg— greatly enlarged (original). 
sion, half an inch or so, and was otherwise uninjured. The balance of 
the marked material was transmitted to me April 24 of the present 
year, and out of some fifteen twigs there was only one in which the 
egg had hatched and the larva gone successfully through its develop- 
ment. In the other cases, as with those previously examined, the egg 
had failed to hatch, or the larva had failed to survive long enough to do 
any noticeable work. The reason for this great mortality is not appar- 
ent, unless it be due to the fact that the cultivated currant, on account 
of difference in growth or greater luxuriance, is not as suitable to the 
insect as wild currants or allied plants, which maybe presumed to have 
