leaf-stalk or bark, and suck with great avidity their contents, which are expelled nearly unchanged, so that however fabulous it may appear, they may literally be said to void a liquid sugar. On looking steadfastly at a group of these insects (_Aphides Salicis_) while feeding on the bark of the willow, their superior size enables us to perceive some of them elevating their bodies and emitting a transparent substance in the form of a small shower. "Nor scorn ye now, fond elves, the foliage sear, When the light aphids, arm'd with puny spear. Probe each emulgent vein till bright below Like falling stars, clear drops of nectar glow." +Evans.+ The _willow_ accommodates the bees in a kind of threefold succession, the farina of the flowers yielding spring food for their young,--the bark giving out propolis for sealing the hives of fresh swarms,--and the leaves shining with honey-dew in the midst of summer scarcity. But to return to the aphides. "These insects may also be seen distinctly, with a strong magnifier, on the leaves of the hazel, lime, &c. but invariably on the inferior surface, piercing the vessels, and expelling the honey-dew from their hinder parts with considerable force." "These might easily have escaped the observation of the earlier philosophers, being usually concealed within the curl of the leaves that are punctured." The drops that are spurted out, unless intercepted by the surrounding foliage, or some other interposing body, fall upon the ground, and the spots may often be observed, for some time, beneath the trees affected with honey-dew, till washed away by the rain. When the leaves of the kidney-bean are affected by honey-dew, their surface assumes the appearance of having been sprinkled with soot. Honey-dew usually appears upon the leaves, as a viscid, transparent substance, sweet as honey, sometimes in the form of globules, at others resembling a syrup, and is generally most abundant from the middle of June to the middle of July. It is found chiefly upon the _oak_, the _elm_, the _maple_, the _plane_, the _sycamore_, the _lime_, the _hazel_ and the _blackberry_; occasionally also on the _cherry_, _currant_, and other fruit trees. Sometimes only one species of trees is affected at a time. The oak generally affords the largest quantity. At the season of its greatest abundance, the happy humming noise of the bees may be heard at a considerable distance from the trees, sometimes nearly equalling in loudness the united hum of swarming. Of the _plane_ there are two sorts; the _oriental_ and the _occidental_, both highly ornamental trees, and much regarded in hot climates for the cooling shade they afford. "Jamque ministrantem Platanum potantibus umbram." +Virgil+