212 NATURE SKETCHES IN TEMPERATE AMERICA 



erected a wall of clay pellets, dividing this first cell from the 

 remainder of the tube which was afterwards added. After 

 the second and third cells were constructed and each in its turn 

 filled with spiders, the final action of sealing up the last sec- 

 tion occurred. 



Usually, in the course of a few days, the egg In each compart- 

 ment hatches into a grub which commences at once to eat and 

 "wax fat" on the rich store of live, paralyzed spiders. By the 

 time the last spider is consumed, the grubs transform into 

 pupae. This mud-dauber, or one that was supposed to be the 

 same individual, afterwards made a second nest by the side of 

 the first tube, which was essentially like the first. I have seen 

 as many as seven nests built in succession side by side on the 

 same rafter or beam, but probably some of these were made by 

 different individuals. 



It is remarkable the great amount of space travelled during 

 the time this wasp was constructing her tube. In an attempt 

 to gain some information of this kind, I tracked her with con- 

 siderable difficulty to the source of supply for her pellets. 

 This I soon found was a wet clay bank on the shore of Lake 

 Michigan, thirty-five yards distant from her nest. This 

 bank, showing an outcropping of wet clay, is reproduced in the 

 plate illustration. Not only the present species obtained her 

 supply of clay here, but several other species of mud-daubers, 

 including all those species known in the neighborhood, came to 

 this point of wet clay for this purpose. I once saw as many as 

 seven individuals gathered here at one time, including Pelopseus 

 and Eumenes. The clay part of the bank is shown at the lower 

 part of the picture as a triangular, darker area. 



I also made an estimate that at least one hundred and fifty 

 pellets were used in nest construction, including an occasional 

 one dropped by the wasp and not recovered. This would give 

 nearly six miles travelled by the wasp in these operations, to say 

 nothing of the distance covered by her foraging expeditions 

 after spiders, which I could not estimate. The white-footed 

 wasp is rarer than Pelopseus, but enjoys a wider distribution, 

 ranging from Canada into South America. 



The observations here related on the nest-making attributes 

 of the white-footed mud-dauber, Trypoxylon albitarse, are of 



