Tachinus pullus Stenus bimaculatus
Philonthus lituratus Rugilus immunis
Jesus College, Cambridge,
January 9th, 1846.
Notes on Aphides with reference to the Plants on which they feed.
By Francis Walker, Esq., F.L.S.
1. Lamium Linn. Archangel.
Species infested. L. album Linn. White archangel.
A small species of Aphis infests this plant, and appears very early in the year, for I found the second generation already in existence at the end of February, 1846. This insect is white, oval, almost transparent, slightly convex, hairy like the plant on which it feeds ; there is a pale buff tinge on the hind part of the abdomen : the antennae are slender, setaceous, hairy, much longer than the body : the mouth is white, and reaches to the base of the middle legs : the eyes are dark brown : the tubes are very short, not more than one-twelfth of the length of the body : the legs are long, slender, and hairy. The young ones are like their mothers, but more linear. The Aphides while walking use their antennae alternately to examine their way before them, and these organs are evidently the seat of the sense of feeling which is highly developed in the insect race, and probably supplies the deficiency of hearing and smelling, though some naturalists have pronounced the antennae to be the organs of one, some of the other, of these facul- ties. Feeling, being the foundation of the other senses, which perhaps are only more highly developed modifications of it, is probably most strong when they are most weak, according to the rule, that the perfection of the lower faculties and of their corresponding organs is accompanied by an equal deficiency of the higher faculties, the general en- dowments of every creature being the same, though separately they are more various than are the species. When the eyes are very large, the antennae are very slight, as in the Libellulae and many of the Diptera. The antennae that are used most in the air are generally knobbed, foliate, or branched as if to gather from all quarters, while those that are employed more often on the earth are usually setaceous or filiform ; the former are comparatively quiescent, the latter very often vibrate rapidly. The antennae of Hy- drophilus, &c. are withdrawn, and the palpi are advanced in the water, but the reverse occurs when the insect comes to land and flies away. The Aphides that feed on bark have less of the peculiar characters of the tribe than those that live on leaves, but more than the species that feed on roots, and thus the three groups constitute a gradation, an epitome of that of the whole creation, which is thus illustrated by Coleridge. "Every rank of creatures, as it ascends in the scale of creation, leaves death behind it or under it. The metal at its height of being seems a mute prophecy of the coming vegetation, into a mimic semblance of which it crystalizes. The blossom flower, the acme of vege- table life, divides into correspondent organs with reciprocal functions, and by instinctive motions and approximations seems impatient of that fixure, by which it is diff"erenced
