The Mason-Wasps 



specimen-jars, I am familiar; but the egg, 

 the larva and the provisions I do not know. 



In compensation, I possess all the details 

 that could be desired about the third species, 

 O. nidulator, Sauss. This insect, like the 

 just mentioned, is ignorant of the art of 

 laying the foundations of its abode and 

 demands a ready-made lodging. Like the 

 Osmias, the Megachiles and the cotton- 

 spinning Anthidia, it wants a cylindrical 

 gallery, either natural or excavated by mi- 

 ners. Its art consists in partitioning a tun- 

 nel and subdividing it into chambers : plast- 

 erer's art, in short. 



Here then, in three species, the only ones 

 whose habits I have had the opportunity of 

 learning, we see three very different trades: 

 the miner's, the resin-worker's and the plast- 

 erer's. In these three guilds I find exactly 

 the same equipment of tools; and I defy the 

 most meticulous magnifying-glass to tell us 

 what organic modification suggests to the 

 one insect the pavement of pebbles upon a 

 bed of resin, to the second the mine-shaft 

 with its guilloched chimney, to the third 

 the alien cylinder, partitioned with mud. 

 No and again no: the organ does not con- 

 stitute the function, the tool does not make 

 the workman. With similar implements, 

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