58 THE PLUM CURCULIO. 
being reared. Further attempts at rearing from pears in this locality 
gave no results. 
May 21 and 23, 1905, at Washington, D. C, and again May 30, 
1905, young KiefTer pears from trees were confined with beetles, and 
eggs were deposited freely. No larvae, however, succeeded in devel- 
oping. 
During the course of the season of 1905 many fallen pears were 
examined by Mr. Johnson at North East, Pa., and he found only a 
single curculio larva, about one- third grown, feeding in the core of a 
pear on the ground. No larvae were found in fruit on the trees. 
Observations on plums, wild and cultivated, in many localities 
show that there is also a high mortality among larvae where the fruit 
remains on the tree or if its dropping be materially retarded. Plums 
punctured while small are more apt to drop than if the fruit is one- 
third grown or over. This dropping of the smaller fruit and the 
shedding of the fruit by the tree itself enables the species to more 
than maintain itself. Larvae hatching in fruit which does not fall are 
ordinarily able to penetrate the flesh but a short distance before 
succumbing, perhaps due to the combined effect of the copious gum 
exuded and the pressure of the growing tissues. The evidence also 
is that the egg may be destroyed by the gum exuding at the punc- 
tured point, and our notes show the examination of many punctures 
in which the egg could not be found, or was crushed, the cavity being 
completely filled with gum. The number of eggs or larvae missing 
has been quite too large to be accounted for otherwise. Many plums 
of the Japanese and Domestica types and of wild native sorts have 
been examined when taken from the trees and bearing egg punc- 
tures, and the conclusion is evident that larvae are not able to survive 
during the rapid growing period, and, as in the case of the apple, 
their successful development depends on the falling of the fruit. 
After the fruit has become grown, and the ripening process begins, 
larvae are more likely to survive, and ripe wormy plums, especially 
of the cultivated Japanese sorts, are not infrequently to be met with. 
The development of the peach, with reference to its availability 
as a host for the curculio, may be divided into three stages. The 
first stage includes the time from the beginning of oviposition to 
near the time when the pits begin to harden, a period of 3 or 4 weeks, 
during which approximately 75 per cent of the total infestation of 
the season occurs. The fruit in this stage, though growing rapidly, 
does not exude gum upon being punctured and readily drops from 
the tree when infested by curculio larvae. (See PI. V, fig. 1.) Prob- 
ably no fruit infested at this time remains long on the tree. The 
second stage in the growth of the peach begins when the pits show 
the first signs of hardening and extends up to the ripening period. 
