REPORT OF THE SOCIETY 43 



following plan : On examination one finds that the CoUetes begins by digging an 

 approximately vertical tunnel, about 8 mm. in diameter, or that of a stout pencil. 

 The length varies, in the majority of cases is about 30 cms., although sometimes 

 only half that length. At this depth the tunnel bends and is obliquely prolonged 

 for a distance of from 4 to 11 cms. At the end of this branch the bee constructs 

 the above mentioned nest on a higher level. It is 2.5 cms. long and .8 cm. broad. 

 The cell prepared, it is then provisioned with honey, not, however, any kind which 

 has anything in common with that of our domestic bee. It is in the form of a 

 rather thick and dark coloured paste, is mixed with nectar and pollen, and has an 

 odour which is far from agreeable. 



A single egg measuring 3.5 mm. x .5 mm. is fixed on to the side of the wall, 

 slightly above the level of the honey with which the cell is half filled. When the 

 egg is laid, an oblique transverse membrane is fastened to the wall 12 mms. from 

 the cell base, which hermetically seals the nest. Above this, there still remains a 

 cell case almost equal in length. The first cell completed, our CoUetes commences 

 another one. To do this she ascends slightly higher up the central gallery and 

 without any regard to the position of the first nest she attacks a second. The 

 soil which is removed from the new tunnel is used to fill up those parts underlying 

 it and to isolate the first cell completely from the others. This fact explains why 

 the nests seem to be irregularly disposed, when one digs at random, and has not 

 the central gallery as a guide. By running plaster into the tunnel, one usually 

 only obtains part of the structure. The presence of other lower branches is then 

 revealed by a spur, which is prolonged for several centimetres beyond the starting 

 point of a side gallery. 



It is difficult to say how many cells can be thus furnished by a single CoUetes. 

 Indeed numerous tunnels are found on the side of a colony, and the different 

 constructions run into one another in such a way as to make it impossible to say 

 whether the cells one meets with belong to the same or different bees. It is 

 perhaps nearer the truth to state that the number of nests of a single gallery does 

 not exceed three or four; but there is nothing to show that the same CoUetes 

 may not construct more than one gallery. 



Meanwhile what is the fate of the egg? Abandoned in the sand, it hatches. 

 The young larva feeds on the reserve nourishment, grows in size, and changes into 

 a pupa, but before transformation takes place, a precaution is taken, which does 

 not lack ingenuity. To protect the flimsy pellicle in which it is imprisoned for 

 long months, against the cold of winter, the larva plasters the walls with its 

 excrement. Slight in appearance as is this tenuous covering which is placed on 

 top of the outer membrane of the cell, the fact that nature has endowed the 

 creature with the instinct to have recourse to such a means of protection means 

 that it must be an efficacious one. The cell from transparency becomes opaque 



