SOME INSECT EXPERIMENTS 139 



domestic turn of mind, and quite different in habits from their mud- 

 daubing cousin, who is a restless, nervous creature of a solitary nature. 



.This insect constructs from five to fifteen cells of rich grey mud, 

 which, upon hardening, becomes quite substantial. The nest is placed 

 in situations similar to those which the paper-making species select. 

 Like the Sphecid wasp, the mud-dauber fills each cell with paralyzed 

 insects, which in this case consist of small spiders. Then, after laying 

 a single egg in each, she seals up the opening with mud and leaves 

 the young wasps to shift for themselves. 



For the first experiment, a mud-dauber's nest was selected which 

 was discovered under the overhanging roof of an old woodshed. The 

 affair consisted of ten cells, all but one of which had been sealed by 

 the wasp, who, by the way, quickly appeared upon the scene, carrying 

 a small, reddish spider. The burdened insect flew directly to the 

 nest and after carefully inspecting her cargo, to make sure that it 

 was in perfect condition and quite proper to serve as food for her 

 offspring, she entered the remaining empty cell. To store these spiders 

 to her satisfaction required quite some time, but when once they had 

 been suitably placed our industrious insect lost no time in hurrying 

 away to gather more victims. This manoeuvre was repeated on an 

 average of every seven minutes, but upon her tenth return to the nest, 

 she carried a small pellet of mud instead of the usual spider. This 

 she carefully placed upon the open end of the cell and after flattening 

 it somewhat with her head and forefeet, flew off for more. 



At this point I intervened in behalf of my experiment, and as a 

 consequence thereof, the sealed portion of the entrance, and the spi- 

 ders, were entirely removed from the cell. Within a very few minutes 

 the wasp returned, bearing its second load of mortar, and this, as 

 upon her previous visit, she cemented to the opening of the cell. Now 

 the wasp thrust her head through the half-closed entrance and after 

 apparently inspecting the empty interior, again flew away, this time, I 



