30 PHIL RAU AND NELLIE RAU 



those few individuals which builded strong survived, until now 

 only this vestige remains of what may have been a former habit. 



An idea of the amount of effort expended in the construction 

 of a, nest can be gained by examining the cross-sections illustrated 

 in figs. 7 and 9, and the longitudinal section in fig. 10. 



The material used in the nest is usually native clay, gray, 

 red or various shades of brown, or even black loam. The 

 Peckhams describe several cells made of white plaster, and I 

 have several nests taken from the walls of a brick-yard stable 

 which have some cells made of brick-dust and the remainder 

 of black mud. Sometimes even the pellets of mud, which make 

 up a single cell are clearly from different sources. 



The favorite nesting-place of these species is the rafters of 

 barns or sheds, especially when they are high and well out of 

 reach of intruders. In areas untouched by man the overhanging 

 rocks and bluffs are favorite nesting-places. One also finds the 

 mud nests on the back of torn or hanging wall-paper, in the 

 folds of horse-blankets, old carpet or grain-sacks hanging in 

 out-buildings, in the sleeves and folds of hanging coats, on old 

 umbrella ribs, on strands of hay or corn-husks or in small spaces 

 between the rafters, but in every such case the nest conforms 

 to its immediate surroundings. It frequently happens that the 

 nests built in close quarters are very beautiful, since the builder 

 cannot obliterate her art here by daubing mud promiscuously 

 all over it. The nests built in folds of cloth or on strands of 

 hay are usually more asymmetrical than those built flat upon 

 a board or an overhanging rock, and conform to the folds of 

 the drapery. 



It was once my good fortune to gather a bushel of mud nests 

 from some freight cars side-tracked in the city. This suggests 

 a mode of the dissemination of the species not heretofore con- 

 sidered, and may well be a large factor in their distribution, 

 since the Peckhams and others think that the wasps do not 

 usually migrate far from the place of their birth. 



On one occasion, when searching for mud nests, I was taken 

 to a farm-house where the nests were abundant in the upstairs 

 rooms. The house had not been occupied for the two years 

 previous to that summer and insects had made themselves at 

 home in it. The nests were abundant upon the walls and 

 window-casings of the upper rooms and many wasps were busily 



