A STOUT WALL 



will not depart unless circumstances compel it to do so. 

 Some of them, for instance, do not make use of mud at all, 

 but cut up either soft or woody plants into small pieces, and 

 after making a true paper -pulp from them employ this 

 material for the homes of their offspring. 



As soon as an Osmia has found a cavity to her liking, she 

 sweeps it out carefully and carries the refuse away to some 

 distance. Then she proceeds to dust it, working towards 

 the opening and throwing the dust outside. If the tunnel 

 be a narrow one, she gathers her store of honey and pollen 

 for the young forthwith, after merely smoothing the walls 

 with a coating of mud wherever it is necessary to do so. 

 But if the cavity appear too wide, the first thing she does 

 is to make a chamber at the far end by building a cross 

 wall, leaving openings at one side; then she furnishes it 

 with a stock of provisions, blocks up the apertures, and 

 begins a second compartment a little further on, and so 

 forth. 



An Osmia that has taken possession of a wide tube begins 

 by closing it with a wall, with the object, apparently, of 

 keeping out other insects which might come and lay their eggs 

 there to the detriment of the lawful owner. In order to 

 construct this partition, she first lays down a circular rim, 

 and adds little by little to its edge, turning round and 

 round with her head pointing on one side of the wall in 

 process of formation, and her body on the other, so that 

 the hinder extremity acts as a trowel, and the wall is pressed 

 between this and the jaws, and is thus gradually smoothed 

 and spread out into a perfectly even layer. The first 

 chambers that are formed in a reed are longer, and have 

 walls which are farther apart, than those which are made as 

 the insect gets nearer the end ; but there is no regular 

 gradation of size. The final wall, which closes the whole 



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