Читать книгу Intelligence in Plants and Animals - Thomas G. Gentry - Страница 14

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Living in chinks and crannies of ranges in our homes, and occasionally in bookcases and closets where glutinous and sugary matters abound, but which has probably not been met with elsewhere, is a strange but beautiful little creature which, as far as can be determined, goes through the brief round of its existence without a name to distinguish it from its fellows.

Few entomologists have given any special attention to its family relationships. The possession of certain bristle-like appendages which terminate the abdomen, and which are no doubt comparable with the abdominal legs of the Myriopods, or Thousand Legs, classes it with the Bristle-tails, or Lepismas. In general form, a likeness to the larva of Perla, a net-veined neuropterous insect, is manifest, or to the narrow-bodied species of Blattariæ, or Cockroaches, when divested of wings.

Lepisma saccharina, of Europe, which is indistinguishable from our ordinary American form, is far from uncommon in old, damp houses. Its structure is less complicated than the heat-loving species to which I have alluded, and there are likewise differences of habits which show themselves to the close investigator of natural phenomena.

Not unlike the cockroaches, which our little denizen of the hearth somewhat vaguely resembles in form, it affects hot, dry localities, and is always astir at nights in quest of its fare, for it disdains the light of the day and the consequent publicity of its deeds of shame and plunder.

Many a housewife in the discharge of duty has unearthed, so to speak, the miscreant from its hidden retreat, and sought by foot or hand to crush the life that dares obtrude its uncleanly presence in her larder, but the cunning, swift-footed Lepisma darts off, like a streak of light, to some near-by crack or breach, where it manages to hide from threatening danger. The bodies of these nimble, silent-moving creatures being coated in a suit of shining mail, which the arrangement of the scales so very much resembles, they have a weird and ghostly look. This appearance, and the swiftness of their movement, which the eye can hardly trace, have led the vivid mind of man, in country town and village, to dub them “silver witches.”

So fleet of foot are they, and so like a wave of blurred light they cross the vision, that it is vain to try to figure what they are in shape and look. In death they yield their all of earth to prying science. Their body’s form is narrow, flattened; their legs in pairs of threes, each of six joints consisting, the basal joints broad, flat, triangular, the tarsal large, in number two, and armed at end with pair of claws incurved. The three thoracic segments are very like in size, and eight abdominals, of similar length and width. So weak it seems the rather long abdomen is, that two pairs or six of bristles, simple, unjointed, and freely movable, serve as support, and also, as in other groups of insects, as organs locomotive.

The mode of antenna-insertion—and the same prevails in the entire family—is much like that of the Myriopods, the front of the head being flattened and concealing, as in the Centipedes, the base of the antennæ. Indeed, the head of any of the Bristle-tails, as seen from above, bears a general resemblance in some of its features to that of the Centipede and its allies, and so, in a less degree, does the head of the larvæ of certain beetles and neuropters. The eyes are compound, the individual facets constituting a sort of heap. The mouth-parts are readily compared with those of the larva of Perla, the rather large, stout mandibles being hid at their tips by the upper lip, which moves freely up and down when the creature opens its mouth. In length the mandible is three times its breadth, and furnished with three sharp teeth on the outer edge, and with a broad cutting margin within, and still further inwards with a number of straggling small spines. The lower lip is broad and stout, with a distinct medium suture, which indicates a former separation in embryonic life into a pair of appendages. Its palpi are three-jointed, the joints being broad, and directed backwards in life, and not forwards, as in the higher insecta.

LEPISMAS AT WORK.

How Books are Destroyed.

Perhaps not more than a half-dozen species of Lepisma are known to exist in this country. Our commonest form is very abundant in the Middle States under stones and leaves in forests, and northward in damp houses, where it has much of the habits of the cockroach, eating clothes, tapestry, silken trimmings of furniture, and doing great mischief to libraries by devouring the paste and mutilating the leaves and covers of books. Our heat-loving form, which is apparently allied to the Lepisma thermophila of Europe, and which may be an imported species, is quite as destructive as its nearest of kin Lepisma saccharina. It does not confine its ravages to closets and pantries, and feed upon sugar and cake and pastry, but has latterly taken to bookcases, where it leads an easy, comfortable life, without fear of molestation.

So delicately constructed are the Lepismas, and so seemingly feeble the breath of life which animates their frail houses of clay, that nature has endowed them with qualities of mind and body which eminently fit them for the part they have to play in the world. She has made them lovers of darkness rather than light, endowed them with keenness of vision and hearing truly wonderful, and given them a celerity of movement which enables them to outstrip in speed the fleetest of their insect-enemies, and even to baffle the well-directed efforts of man for their destruction. The silver-coated armor with which they are invested is so glossy and smooth that they can slip into a crevice in the wall or floor with the utmost ease and facility. From their actions it would seem that they were always on the alert, for when peril is imminent they do not run aimlessly about for a place of security, but know just where to find it with the least possible expenditure of time and physical strength. Every nook and cranny of their appropriated domain is as well known to these very humble of God’s creatures as some forest-tract of country to one skilled in wood-craft. Never have I studied the behavior of Lepisma that I have not been deeply impressed with the intelligence of its actions. There have always been displayed a purpose and an aim, which showed as plainly as could be that no blind instinct was the cause of a conduct so rational and human-like.