358 



CARL HARTMAN 



In this work of smoothing each load of mud the front tarsi 

 meet at an angle approximating ninety degrees. Thus it hap- 

 pens that at the apex of the angle, that is, around the claws 

 of the feet, more mud generally gathers than at other points. 

 Frequently the work is left before this lump is perfectly smoothed 

 out and as a result a permanent papilla or tubercle remains 



Fig 6 W<>=- : 



Fig 4 



when the mud hardens. As the wasp works with the feet on 

 the outside of the nest, the tubercles appear as the "decora- 

 tive features," the " sculp turings " of the nest, to which various 

 authors have made reference (fig. 7). On the average about 

 fifteen tubercles appear on one nest. A little less than half of 

 the loads are, therefore, smoothed off perfectly, leaving no 

 tubercle. 



