INSTINCT OF INSECTS. 579 



substitution of mitys for the first range of waxen cells, this ])rocec]ure 

 invariably look place in every bee-hive at z fixed period — when, for exam- 

 ple, the combs are two thirds filled with honey — it would be less surpris- 

 ing ; but there is nothing of this invariable character about it. It does 

 not, as Huber expressly informs us^, occur at any marked and regular 

 period, but appears to depend on several circumstances not always com- 

 bined. Sometimes the bees content themselves with bordering the sides 

 of the upper cells with propolis alone, without altering their form or 

 giving them greater thickness. And it is not less remarkable that, from 

 the instances last cited, it appears that they are not confined to one 

 kind of cement for strengthening and supporting their combs, but avail 

 themselves of propolis, wax, or a mixture of both, as circumstances 

 direct. 



Not to weary you with examples of the modifications of instinct we are 

 considering, I shall introduce but three more : — the first, of the mode in 

 which bees extend the dimensions of an old comb ; the second, of that 

 which they adopt in constructing the male cells and connecting them with 

 the smaller cells of workers ; and the last, of the plan pursued by them 

 when it becomes necessary to bend their combs. 



You must have observed that a comb newly made becomes gradually 

 thinner at its edges, the cells there, on each side, progressively decreasing 

 in length ; but in time these marginal cells, as they are wanted for the 

 purposes of the hive, are elongated to the depth of the rest. Now sup- 

 pose bees, from an augmentation of the size of their hive, to have occa- 

 sion to extend their combs either in length or breadth, the process which 

 they adopt is this : — they gnaw away the tops of the marginal cells until 

 the combs have resumed their original lenticular form, and then construct 

 upon their edges the pyramidal lozenge-shaped bottoms of cells, upon 

 which the hexagonal sides are subsequently raised, as in their operation 

 of cell-building. This course of proceeding is invariable : they never 

 extend a comb in any direction whatever without having first made its 

 edges thinner, diminishing its thickness in a portion sufficiently large 

 to leave no angular projection. Huber observes, and with reason, in 

 relating this surprising law which obliges bees partially to demolish the 

 cells situated upon the edges of the combs, that it deserves a more close 

 examination than he found himself competent to give it; for if we may 

 to a certain point form a conception of the instinct which leads these 

 animals to employ their art of building cells, yet how can we conceive 

 of that which in particular circumstances forces them to act in an oppo- 

 site direction, and determines them to demolish what they have so labori- 

 ously constructed ?^ 



Drones, or male bees, are more bulky than the workers ; and you have 

 been told, in speaking of the habitations of insects, that the cells which 

 bees construct for rearing the larvae of the former are larger than those des- 

 tined for the education of the larvae of the latter. The diameter of the cells 

 of drones is always 3i lines (or twelfths of an inch), that of those of work- 

 ers 2- lines ; and these dimensions are so constant in their ordinary cells, 

 that some authors have thought they might be adopted as an universal 

 and invariable scale of measure, which woidd have the great recommenda- 



* Huber, ii. 234. note *. ^ i^^^_ jj^ 228. 



