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:-- I 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 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 good.[74] FOOTNOTES: [71] _Loc. cit._, p. 189. [72] _Ibid._, p. 119. [73] _Geistesleben der Thiere_, pp. 194 and 199-200. [74] Phil. Trans., _loc. cit._ CHAPTER VI. SPIDERS AND SCORPIONS. _Emotions._