Ł 
being known, partly by the presence of the little I ag: bene 
jar 
account that probably less than a dozen of these larva W 
ported to 
280 NATURE’S MEANS OF LIMITING THE NUMBERS OF INSECTS. 
of them, indeed, Pog! Ai minute that they cannot easily wa seen 
without the aid of al and the constant difficulty of manipu- 
lating them have ae Wei a somewhat chimerical aspect to 
the suggestion, and have caused it to be regarded as more ingen- 
ious than practicab 
“In the course of our coho eet? of the oyster-shell b 
their destruction. 
this state where the examinations were aie. that more than 
of the bark lice had been destroyed by this parasite, its operations | 
through which the chaicis flies had escaped. It was also found, by — 
examining the scale, late in the fall, that one brood of, the ones : 
des hibernated in the larva state beneath the scales. The a 
therefore, readily occurred that this was a very favo rab ally 
tunity for testing the practicability of igre pale nde frien F 
parasites to those parts of the country in which their presence 
cannot now be detected, We had previously reod several pac: of 
ages of apple twigs from different localities in the northern part 0 
Illinois and the southern part of Wisconsin, heayily infested wt 
“Captain Edward H. Beebe, of Galena, who had been passing 
winter in Geneva, and who had taken a lively interest in ria 
vestigation, undertook to conduct this nag Bag ote eee 
ena, 
orchards, im 
= of rr which were known to be or infested. by ! 
bark 
“When we consider the minute size of these insects, the ily 
matured fly (Fig. 72) being only one twenty-fifth of an m 
veals the operation of the chalcis is so minute that it 
seen by the aid of a magnifying glass; and we Arthar | 
) the new locality, and that the small number 0 of 
, 
