CABDER BEES. 463 



One of the most curious points in the construction of this 

 nest is the manner in which it is suspended to the branch. 

 As is shown in the illustration, the combs are comparatively 

 narrow at the point of attachment, and gradually increase in 

 width, so that their weight, when filled with the young brood, 

 must be considerable, and the strain on the upper part of the 

 comb very great. The manner in which the insect has met this 

 difficulty is really wonderful. It has not made the upper part of 

 the comb to consist of a solid mass, as is the case with the clay 

 nest which has just been described, but has utilized almost every 

 portion of the comb from the top to the bottom. But, in order 

 to obtain the needful strength, the upper part is constructed 

 after a raannur that is widely different from that which prevails 

 upon tbe lower and wider portion of the comb. 



If one of the combs were broken across, the lower half would 

 much resemble, except in colour, the nest of an ordinary wasp, 

 except that the cells are smaller, and the material stronger. But, 

 towards the top, the partitions between the cells become thicker, 

 and in consequence the cells are fewer. This increased strength 

 is chiefly foimd in the partitions which run perpendicularly, 

 and which are so thick, that the hexagonal form of the cells 

 becomes obscured, the great object being, not the exact shape 

 of the cells, but their ability to bear the weight of the comb 

 below. 



The general effect of this modification can be easily imitated 

 by taking an oblong piece of linen, rounding the comers, and 

 plaiting one end, just as ladies gather in the upper part of an 

 apron. The longitudinal folds will then represent the perpen- 

 dicular partitions of the cells, and wiU show how strength ia 

 gained without needless expenditure of material The strengthened 

 partitions do not run quite perpendicularly, but are slightly 

 irregular, just as would be the case with the folds of the linen if 

 it were fastened to a branch by the plaited end, and suffered to 

 hang loosely. 



The history of Social Insects would be incomplete without the 

 mention of several British insects, which are plentiful enough, 

 but which are scareely known as well as they deserve. These 

 are the creatures which are popularly known as Cabder Bees, 

 because they prepare the materials for their nest in a manner 



