The Cotton-bees 



Anthldla be air-proof, owing to some modi- 

 fication that escapes me? In any case, this 

 impermeabihty cannot be attributed to the ex- 

 cremental mosaic, which the cocoons of the 

 resin-working Anthidia do not boast, though 

 they are endowed with an apex of the very 

 best. 



Shall we find an answer to the question in 

 the varnish with which the silken fabric is im- 

 pregnated? I hesitate to say yes and I hesi- 

 tate to say no, for a host of cocoons are coated 

 with a similar lacquer though deprived of 

 communication with the outside air. All said, 

 without being able at present to account for 

 its necessity, I admit that the apex of the An- 

 thidia is a breathing-aperture. I bequeath 

 to the future the task of telling us for what 

 reasons the collectors of both cotton and resin 

 leave a large pore in their shells, whereas all 

 the rest of the weavers close their cocoons 

 completely. 



After these biological curiosities, it remains 

 for me to discuss the principal subject of this 

 chapter: the botanical origin of the materials 

 of the nest. By watching the insect when 

 busy at its harvesting, or else by examining 

 its manufactured flock under the microscope, 



293 



