500 HABITATIONS OF INSFXTS. 



constancy of climate, too, occasions frequent internip- 

 tions, and injures the syuimetrv of the combs ; for a 

 work resumed is always less perfect than one followed 

 up until completed. 



At first the substance of the cells is of a dead white, 

 semitransparent, soft, and tliough even, not smooth : 

 but in a few days it loses n;ost of these qualities, or 

 rather acquires new ones; a yellow tint spreads over 

 the cells, particularly their interior surface ; their 

 edges become thicker, and they have acquired a con- 

 sistence, which at first they did not possess. The 

 combs also when finished are heavier than the unfi- 

 nished ones : these last are broken by the slightest 

 touch, whereas the former will bend sooner than break. 

 Their orifices also have something adhesive, and they 

 melt less readily ; w hence it is evident that the finish- 

 ed combs contain something not present in the unfi- 

 nished ones. In examining the orifice of the yellow 

 cells, their contour appeared to the younger Huber to 

 be besmeared with a reddish varnish, unctuous, strong- 

 scented, and similar to, if not the same as, propolis. 

 Sometimes there w ere red threads in the interior, which 

 were also applied round the sides, rhombs, or trape- 

 ziums. This solder, as it may be called, placed at 

 the point of contact of the different parts, and at the 

 summit of the angles formed by their meeting, seemed 

 to give solidity to the cells, round the axis of the 

 longest of which there were sometimes one or two 

 red zones. From subsequent experiments, M. Huber 

 ascertained that this substance was actually propolis^ 

 collected from the buds of the poplar. He saw them 

 with their mandibles draw a threa4 from the mass of 



