Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/503

Rh temperature is remarkably exemplified in bees, among which, in consequence of their collecting together in large numbers, the heat is not readily dissipated, and admits also of being easily ascertained by the thermometer. Hunter found it to vary from 73 to 84 Fahr. ; and Huber observed it on some occasions to rise suddenly from about 92 to above 104.

The physiology of the external senses in a class of animals of a nature so remote from our own species must necessarily be very imperfectly understood by us. The infinite diversity of character presented by the different tribes of insects, as well as of other animals, naturally sug gests the idea that external objects produce on their sentient organs impressions widely different from those which they communicate to ourselves. The notions we form of their senses must not only be liable to great inaccuracy, but may often be totally inadequate representations of the truth. A finer organisation and more subtile perceptions would alone suffice to extend the sphere of their ordinary senses to an inconceivable degree, as the telescope and the micro scope have with us extended the powers of vision. But they possess in all probability other organs appropriated to unknown kinds of impressions, which must open to them avenues to knowledge of various kinds to which we must ever remain total strangers. Art has supplied us with many elaborate modes of bringing within our cognizance some of the properties of matter which nature has not immediately furnished us with the means of detecting. But who will compare our thermometers, spectroscopes, or hygrometers, however elaborately constructed, with those refined instruments with which the lower orders of animals, and particularly insects, are so liberally provided?

The antennae, which are so universally met with in this class of animals, are doubtless organs of the greatest importance in conveying impressions from without. Their continual motion, the constant use which is made of them in examining objects, the total derangement in the instincts of those insects which have been deprived of them, point them out as exquisite organs of sense. To impressions of touch arising from the immediate contact of bodies they are highly sensitive, but their motions evidently show that they are affected by objects at some distance. They are, no doubt, alive to all the tremulous movement of the sur rounding air, and probably communicate perceptions of some of its other qualities. Composed of a great number of articulations, they are exceedingly flexible, and can readily embrace the outline of any body that the bee wishes to examine, however small its diameter. Newport, in a paper published in the Transactions of the Entomological Society, says he is convinced from experiments that the antennae are auditory organs ; and that however varied may be their structure, they are appropriated to the perception and transmission of sound. The majority of modern physiologists and entomologists coincide in this view, and the weight of authority in favour of it is certainly very great, comprising as it does Sulzer, Scarpa, Schneider, Borkhausen, Bonsdorf, Carus, Straus- Durckheim, Oken, Burmeister,Kirby and Spence, Lespes, and Hicks. Nevertheless, other eminent entomologists, as, for instance, Lyonet, Kuster, Robineau- Desvoidy, Vogt, and Erichson, regard these organs as the seat of smell The question may be considered. as yet undetermined, and it is possible that they are the organs of some sense of which we know nothing, and which we con sequently cannot describe. It is by these instruments that the bee is enabled to execute so many works in the interior of the hive, from which the light must be totally excluded. Aided by them it builds its combs, pours honey into its magazines, feeds the larvas, and ministers to every want which it appears to discover and judge of solely by the sense of touch. The antennae appear also to be the principal means employed for mutual communication of impressions. The different modes of contact constitute a kind of language which seems to be susceptible of a great variety of modifications, capable of supplying every sort of information for which they have occasion.

The sense residing in the antenna3 appears to be on many occasions supplementary to that of vision, which in bees, as in other insects, is less perfect than in the larger animals. During the night, therefore, they are chiefly guided in their movements by the former of these senses. In full daylight, however, they appear to enjoy the sense of vision in great perfection. A bee alights unerringly on the flowers in search of nectar or pollen, and as truly at its own hive a entrance on its arrival there. When returning from the fields to its hive it seems to ascertain the proper direc tion by rising with a circular flight into the air ; it then darts forward with unfailing precision, passing through the air in a straight line with extreme rapidity, and never failing to alight at the entrance of its own hive, though whether its course be determined by vision alone we are unable to say.

Their perceptions of heat and cold are extremely delicate. The influence of the sun s rays excites them to vigorous action. Great cold will reduce them to a state of torpor, and inferior degrees of cold are unpleasant to them ; a temperature of 40 Fa-hr. will so benumb a bee as to de prive it of the power of flight, and it will soon perish unless restored to a warmer atmosphere. When, however, bees are in the usual winter s cluster in the hive, they will bear a very great degree of cold without injury. In America hives often stand where the external temperature is as low as 20 below zero, and from the condensed vapour within the hive, the bees may be found in a solid lump of ice, and yet, with returning spring, they awake to life and activity. The degree of cold which bees can endure has not been ascertained, though it is no doubt considerable. They survive the winter in many cold parts of Russia, in hollow trees, without any attention being paid to them ; and their hives are frequently made of the bark of trees, which does not afford a very complete protection from the effects of frost. Many bees which are thought to die of cold in winter die in reality of famine or damp. A rainy summer and cold autumn often prevent their laying in a sufficient store of provisions ; and the hives should, therefore, be carefully examined in the after-part of the season, and the amount of food ascertained. Mr White judiciously observes, that bees which stand on the north side of a building whose height intercepts the sun s beams all the winter will waste less of their provisions than others which stand in the sun ; for, coming forth seldom, they eat little, and yet are as forward in the spring to work and swarm as those which had twice as much honey left with them the preceding autumn. They show by their conduct that they are sensible of changes in the state of the weather for some time before we can perceive such alterations. Sometimes when working with great assiduity they will suddenly desist from their labours, none will stir out of the hive, while all the workers that are abroad hurry home in crowds, and press forward so as to obstruct the entrance of the hive. Often, when they are thus warned of the approach of bad weather, we can distinguish no alteration in the state of the atmosphere. Gathering clouds sometimes produce this effect on them ; but perhaps they possess some species of hygrometrical sense unconnected with any impression of vision. Huber supposes that it is the rapid diminution of light that alarms them, for if the sky be uniformly overcast they proceed on their excursions, and even the first drops of a shower do not make them return with any great precipi tancy.