THE EUMENIDAE 339 



stalk was about eighteen inches high and seven-eighths inch 

 in external diameter, while the diameter of the hollow 

 within was a little more than three-eighths inch. One must 

 admit that this is quite a cavity for so small a mason to 

 partition off. The top was broken off, thus offering easy 

 access to the mother wasp. The inside was weathered, and 

 some rings of mud about the periphery disclosed the fact 

 that last year was not the first season that the stem had been 

 in use. Not the entire gallery in the stem, but only the 

 upper porion, was partitioned. The nest at present occu- 

 pying it commenced at a point six inches from the top, 

 where a heavy bottom of mud, one-half inch thick, had 

 been placed for a foundation or floor ; below this the hollow 

 was empty and unused, and weathered from previous er^ 

 posure. This shows conclusively that in this case the 

 mother had not been compelled to do any tunnelling, but 

 the elder stalk as she found it was already tenantable. 



The figure shows (see fig. 68) the single solid chunk 

 of mud for a platform at the bottom, another layer near to 

 this base and so close in sortie places as almost to touch the 

 platform layer. Similarly, each partition was composed 

 of two separate walls. The intervening space was usually 

 sufficient to admit a fine pin, but in one case the two walls 

 were one-fourth inch apart. The cells, as the figure shows, 

 were three-eighths to one-half inch in length. 



Upon opening the twig in May, we found three wasps 

 completely developed, wings and all. They moved about 

 and, with a little prodding, walked out of the cell. While 

 we were speculating as to whether they had become mature 

 very early in the season, or possibly the previous autumn, 

 and were only awaiting the warmth of spring to come forth, 

 we opened two other cells and there found the wasps com- 

 pletely developed except that the wings were not inflated. 

 Hence, it is logical to conclude that these specimens had just 



