INSTINCT 223 



food might become developed; and the foreign ants thus unin- 

 tentionally reared would then follow their proper instincts, and 

 do what work they could. If their presence proved useful to the 

 species which had seized them — if it were more advantageous to 

 this species, to capture workers than to procreate them — the habit 

 of collecting pupae, originally for food, might by natural selection 

 be strengthened and rendered permanent for the very different 

 purpose of raising slaves. When the instinct was once acquired, if 

 carried out to a much less extent even than in our British F. san- 

 guinea, which, as we have seen, is less aided by its slaves than the 

 same species in Switzerland, natural selection might increase and 

 modify the instinct — always supposing each modification to be of 

 use to the species — until an ant was formed as abjectly dependent 

 on its slaves as is the Formica rufescens. 



CELL-MAKING INSTINCT OF THE HIVE-BEE 



I will not here enter on minute details on this subject, but will 

 merely give an outline of the conclusions at which I have arrived. 

 He must be a dull man who can examine the exquisite structure of 

 a comb, so beautifully adapted to its end, without enthusiastic 

 admiration. We hear from mathematicians that bees have prac- 

 tically solved a recondite problem, and have made their cells of 

 the proper shape to hold the greatest possible amount of honey, 

 with the least possible consumption of precious wax in their con- 

 struction. It has been remarked that a skilful workman with fitting 

 tools and measures, would find it very difficult to make cells of 

 wax of the true form, though this is effected by a crowd of bees 

 working in a dark hive. Granting whatever instincts you please, it 

 seems at first quite inconceivable how they can make all the neces- 

 sary angles and planes, or even perceive when they are correctly 

 made. But the difficulty is not nearly so great as it first appears: 

 all this beautiful work can be shown, I think, to follow from a few 

 simple instincts. 



I was led to investigate this subject by Mr. Waterhouse, who 

 has shown that the form of the cell stands in close relation to the 

 presence of adjoining cells; and the following view may, perhaps, 

 be considered only as a modification of his theory. Let us look to 

 the great principle of gradation, and see whether Nature does 

 not reveal to us her method of work. At one end of a short series 

 we have humble-bees, which use their old cocoons to hold honey, 

 sometimes adding to them short tubes of wax, and likewise making 

 separate and very irregular rounded cells of wax. At the other end 

 of the series we have the cells of the hive-bee, placed in a double 



