THE EUMENES 205 



symmetrical cupola, a spherical skull-cap, with, at the 

 top, a narrow passage just wide enough for the insect, 

 and surmounted by a neatly funneled neck. It suggests 

 the round hut of the Eskimo or of the ancient Gael, 

 with its central chimney. Two centimeters and a half,^ 

 more or less, represent the diameter, and two centi- 

 meters ^ the height. When the support is a perpendicu- 

 lar plane, the building still retains the domed shape, but 

 the entrance- and exit-funnel opens at the side, upwards. 

 The floor of this apartment calls for no labor: it is sup- 

 plied direct by the bare stone. 



Having chosen the site, the builder erects a circular, 

 fence about three millimeters ^ thick. The materials 

 consist of mortar and small stones. The insect selects 

 its stone-quarry in some well-trodden path, on some 

 neighboring road, at the driest, hardest spots. With 

 its mandibles, it scrapes together a small quantity of 

 dust and saturates it with saliva until the whole becomes 

 a regular hydraulic mortar which soon sets and is no 

 longer susceptible to water. The Mason-bees have 

 shown us a similar exploitation of the beaten paths and 

 of the road-mender's macadam. All these open-air 

 builders, all these erectors of monuments exposed to 

 wind and weather require an exceedingly dry stone-dust ; 

 otherwise the material, already moistened with water, 

 would not properly absorb the liquid that is to give it 

 cohesion; and the edifice would soon be wrecked by 

 the rains. They possess the sense of discrimination of 



1 .97 inch. — Translator'' s Note. 

 2 .78 inch. — Translator's Note. 

 3. 1 18 inch. — Translator's Note. 



