: oe selves in the same manner in warrin ainst other Scolyti- 
-larvee or grubs of Plegaderus discisus destroy the young of | 
‘will form such a minimum as will be quite unimportant. 
. We have seen how wonderfully fertile is the plant louse, 
‘still more surely and effectually perform the work of destruction. 
ing 
stenographus) lays its eggs under the bark, the Platysom 
278 NATURE’S MEANS OF LIMITING THE NUMBERS OF INSECTS. 
of injurious and beneficial insects, I would urge the importan 
a carefully conducted series of observations by some of our 
tical ornithologists and entomologists working in conjunctio 
From May until October one or several. specimens of our mo 
common insectivorous birds, as well as those occasionally 
and a list made of the species of insects found in their stom 
the number of specimens, with other remarks. From the data 
collected we shall be able to form an intelligent opinion as to the” 
vexed question, how far the birds devour indiscriminately inju- 
rious and beneficial insects; and I venture to predict that it will A 
be found that the number of ichneumon and other beneficial kinds 
By far the most important agency in nature, and one almost in- 
calculable in its effects, is the warfare of insects upon each other. 
it may not lay an egg. Now the immense powers of multip a 
tion of individuals in this and all other insects are held in check by 
carnivorous insects. One-half of the insects make war upon the : 
other half. Insects attack one another in various ways, either by 
the stronger directly devouring the weaker; or as parasites they 
Among the external though less known enemies belonging © 
the order of beetles, which Perris enumerates from his exten® 
observations on their habits, are a large number which live under 
the bark of trees. I quote his accounts of them, premising ™ 
we have similar insects with like habits in this country; amd 
though the list of scientific names seems formidable, yet there ' 
no common names for them. I use nearly bis own words, with 
occasional interpolations of English names. 
“ When one of the Scolytids injurious to pines (the p Oe 
b pee 
gum introduces itself by the hole which has given entrance to the 
first insect, it lays its eggs in the gallery of the Bostt 
. ee those eggs are born the carnivorous larve which devol 
of the wood-eating beetles. Other beetles conduct 
X 
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