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 

 Gate, 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 eggn had failed 

 to develop, and the twig had merely died back from the point of exci- 



FiG. 42. — Phylloecus flaviveniris : 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 i^resent 

 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 tho.se 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 may be presumed to have 



