35 



dling around their parents so closely as to entirely cover the twig, leaf-stem, or portion of 

 the leaf on which they are feeding ; indeed it is not uncommon to find them two deep, a 

 portion of the crowded host standing upon the backs of others, all intent on the one 

 business namely, that of absorbing the juice of the tree, which they do by inaerting their 

 beaks into the succulent portions. They seem never to suflfer from over-crowding. Dr. 

 Fitch estimates — his calculation being based on actual count — that the two surfaces of a 

 small leaf, but an inch long, would furnish ample space to accommodate a thousand of 

 these insects. 



When we consider the rapid rate of increase which prevails among the aphides, some 

 details of which we have already given, it is not astonishing that the leaves, leafstalks, 

 tender twigs, and even the fruit-stems are so soon found to be swarming with these pests, 

 their black bodies literally covering every succulent portion, while all around flies, wasps, 

 and other insects are swarming, keeping up a constant buz and hum about the infested 

 tree, to which they are attracted by the sweet licpiid which exudes from the bodies of 

 these aphides. By the end of June they have usually attained their maximum numbers, 

 for by this time their numerous enemies, which we shall hereafter refer to more in detail, 

 have become so multiplied as to begin to get the better of them, and when once the scale is 

 turned against them they are sometimes destroyed so rapidly and entirely that in a few 

 days not a living specimen can be found, the empty skins of the slain being the only remain- 

 ing relics of the vast hordes but recently seen. Dr. Fitch well remarks, " It is by looking at 

 the works of nature in a definite manner, aud tracing out her operations specifically and 

 in their minute details that we arrive at some faint conceptions of their magnitude and 

 grandeur, and become vividly impressed with the truth that no other agency than that of a 

 Creator infinite in wisdom and power could have peopled the world which we inhabit with 

 such countless numbers, and such an endless variety of objects animate and inanimate, each 

 occupying its appropriate sphere, and all so arranged as to fulfil the objects for winch they 

 were called into existence. Has the reader as he has passed a forest ever attempted to 

 conjecture the number of trees which it contained ] and has his mind passed onward to a 

 surmise of the probable number of leaves growing upon each tree, and onwards still to 

 the number of insects which may be drawing their sustenance from each one of these 

 leaves ; and still further to the number of minute and infinitesimal parasites which may 

 be subsisting ujion these insects 1 " Such reflections could scarcely fail to lead the thought- 

 ful observer " from nature up to nature's God." 



During July the cherry tree generally enjoys some respite from the attacks of these 

 tiny foes, but early in August they usually appear again to increase and multiply until 

 being again overtaken by their enemies they are a second time overcome, this later brood 

 is seldom as numerous as the first one. This black aphis seems to be restricted to the 

 cultivated cherry, for we never find them invading any of our native or wild cherry trees, 

 and these in turn seem each to have a species of plant louse peculiar to them, which sel- 

 dom if ever attach themselves to the foliage of other kinds. Dr. Fitch has described in 

 his first report on the noxious insects of New York, a green species Aphis cerasi/ulice which 

 affects the undersides of the young and tender leaves of the choke cherry, and refers to 

 another which infests the wild black cherry. 



Thus wemight go on enumerating and describing species after species to the exhaustion 

 of the patience of our readers, for there is scarcely a tree, shrub, or plant, which is not at 

 some period or other in the year infested with them. We would, however, particularly 

 mention the currant plant louse Ajihi-si ribis, which swarms on our currant bushes, and 

 which ha.s prol)ably been imported into this country from Europe ; the Cabbage-plant 

 louse Aphis hrassic(f, also introduced from Europe ; the Hop-plant louse Ajihis hiiniuli, and 

 the Graiti-plant louse Aphis avena, since these from their great abundance frequently 

 attract general attention. 



We nowpropose to refer to the remedies which nature has provided, and man has 

 devised for the destruction of these tiny foes, and beginning with the more imi)ortant and 

 most eflVctive, we shall first advert to the natural enemies of the plant lice. It lias been 

 truly said, " the plant louse has but one friend — the ant, but its enemies are legion ; and 

 wisely is it so arranged, for were they permitted to increase and multiply at their natural 

 rae without material check, ere a few months had elapsed every green thing on the face 

 ofthe earth would be so covered with them as to cause general destruction. 



