each time that one set never fight, and the other never work, however great the need may be.'1

Similar facts have been observed by Fritz Müller of the South American species.

The Termites, being like the Ecitons blind, like them make all their expeditions under the protection of covered ways. These are underground tunnels in all cases where circumstances permit, but on arriving at a rock or other impenetrable obstruction, they build a tubular passage upon the surface. According to Büchner,

They can even carry their viaducts through the air, and that in such bold arches that it is difficult to understand how they were projected. In order to reach a sack of meal which was well protected below, they broke through the roof of the room in which it was, and built a straight tube from the breach they had made down to the sack. As soon as they tried to carry off their booty to a safe place, they became convinced that it was impossible to pull it up the straight road. In order to meet this difficulty, they adopted the principle of the smooth incline, the use of which we have already seen in the interior of their nests, and built close to the first tube a second, which wound spirally within, like the famous clock tower of Venice. It was now an easy task to carry their booty up this road and so away. . . Either from the desire to remain undiscovered, or from their liking for darkness, they have the remarkable habit of destroying and gnawing everything from within outwards, and of leaving the outside shell standing, so that from the outside appearance the dangerous state of the inside is not perceptible. If, for instance, they have destroyed a table or other piece of household furniture, in which they always manage from the ground upwards to hit exactly the places on which the feet of the article rest, the table looks perfectly uninjured outside, and people are quite astonished when it breaks down under the slightest pressure. The whole inside is eaten away, and only the thinnest shell is left standing. If fruits are lying on the table, they also are eaten out from the exact spot on which they rest on the surface of the table.

In similar fashion things consisting wholly of wood, such as wooden ships, trees, &c., are destroyed by them so that they finally break in with out any one having noticed the mischief. Yet it is said that they go so prudently to work in their de

1 Ibid., p. 119.

struction that the main beams, the sudden breakage of which would threaten the whole building and themselves therewith, are either spared, or else so fastened together again with a cement made out of clay and earth that their strength is greater than ever! (?) Hagen also states that they never cu right through the corks which stop up stored bottles of wine, but leave a very thin layer, which is sufficient to prevent the outflow of the wine and the consequent destruction of the worker: The same author relates that in order to reach a box of wax lights they made a covered road from the ground up to the second story of a house.1

It is needless to give a special description of any of the other habits of these insects, such as their swarming, breeding, &c., for they all more or less closely resemble the analogous habits of ants and bees. It is very remarkable that insects of two distinct orders should both manifest such closely similar social habits of such high complexity, and it rather surprises me that more has not been made of this point by writers opposed to the principles of evolution. Of course if the point were raised, the argument in answer would require to be, either that the similar instincts were derived from common and very remote progenitors (in which case the fact would form by far the most remarkable instance of the permanency of instincts among changing species), or more probably, that similar causes operating in the two orders have produced similar effects-complex and otherwise unique though these effects undoubtedly are.

In connection with the theory of evolution I may conclude this chapter with the following quotation from Smeathman, as it shows how natural relation may develop for the benefit of the species instincts which are detrimental to the individual. Speaking of the soldiers he says:

1 was always amused at the pugnacity displayed when, in making a hole in the earthy cemented archway of their covered roads, a host of these little fellows mounted the breach to cover the retreat of the workers. The edges of the rupture bristled with their armed heads as the courageous warriors ranged

'Geistesleben der Thiere, pp. 194 and 199–200.

themselves in compact line around them. They attacked fiercely any intruding object, and as fast as their front ranks were destroyed, others filled up their places. When the jaws closed in the flesh, they suffered themselves to be torn in pieces rather than loosen their hold. It might be said that this instinct is rather a cause of their ruin than a protection when a colony is attacked by the well-known enemy of termites, the ant-bear; but it is the soldiers only which attach themselves to the long worm-like tongue of this animal, and the workers, on whom the prosperity of the young brood immediately depends, are left for the most part unharmed. I always found, on thrusting my finger into a mixed crowd of termites, that the soldiers only fastened upon it. Thus the fighting caste do in the end serve to protect the species by sacrificing themselves to its good1

Phil. Trans., loc. cit

CHAPTER VI.

SPIDERS AND SCORPIONS.

Emotions.

THE emotional life of spiders, so far as we can observe it as expressed in their actions, seems to be divided between sexual passion (including maternal affection) and the sterner feelings incidental to their fiercely predatory habits. But the emotions, although apparently few and simple in character, are exceedingly strong in force. In many species the male spider in conducting his courtship has to incur an amount of personal danger at the hands (and jaws) of his terrific spouse, which might well daunt the courage of a Leander. Ridiculously small and weak in build, the males of these species can only conduct the rites of marriage with their enormous and voracious brides by a process of active manœuvring, which if unsuccessful is certain to cost them their lives. Yet their sexual emotions are so strong that, as proved by the continuance of the species, no amount of personal risk is sufficient to deter them from giving these emotions full play. There is no other case in the animal kingdom where courtship is attended with any approach to the gravity of danger that is here observable. Among many animals the males have to meet a certain amount of inconvenience from the coquetry or disinclination of the females; but here the coquetry and disinclination has passed into the hungry determination of a ferocious giantess. The case, therefore, because unique, is of interest from an evolutionary point of view. We can see a direct advantage to species from the danger incurred by males on account of mutual jealousy; for this, giving rise to what Mr. Darwin has

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called the law of battle,' must obviously be a constant source of the creation and the maintenance of specific proficiency; the law of battle determines that only the strongest and most courageous males shall breed. But the benefit to species is not so obvious where the danger of courtship arises from the side of the female. Still, that there must be some benefit is obvious, seeing that the whole structure of the male, if we take that of the female as the original type, has been greatly modified with reference to this danger: had the latter been wholly useless, either it would not have been allowed to arise, or the species must have become extinct. The only suggestion I can make to meet this aberrant case is that the courage and determination required of the male, besides being no doubt of use to him in other relations in life, may be of benefit to the species by instilling these qualities into the psychology both of his male and female descendants.

The courage and rapacity of spiders as a class are too well and generally known to require special illustration. One instance, however, may be quoted to show the strength of their maternal emotions. Bonnet threw a spider with her bag of eggs into the pit of an ant-lion. The latter seized the eggs and tore them away from the spider; but although Bonnet forced her out of the pit, she returned, and chose to be dragged in and buried alive rather than leave her charge.

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The only other point that occurs to me with reference to the emotions of spiders is the somewhat remarkable one concerning their apparent fondness of music. The testimony is so varied and abundant on this matter that we can scarcely doubt the truth of the facts. These simply are that spiders—or at any rate some species or individuals --approach a sounding musical instrument, especially when the music is tender and not too loud.' They usually approach as near as possible, often letting themselves down from the ceiling of the room by a line of web, and remain suspended above the instrument. Should the music become loud, they often again retreat. Professor C. Reclain, during a concert at Leipsic, saw a spider descend in this way from one of the chandeliers while a violin solo