THE WOOD-BOBEES. 11 



CHAPTER YIII. 



THE WOOD-BORERS. 



Trypoxylon albopilosum Fox and Trypoxylon riibrocinctum 



Packard. 



Plate XIV., fig. 1. 



In the autumn of 1895 we publislied some notes on these two 

 species.* Since that time we have given a good deal of atten- 

 tion to these wasps and have gathered some new facts as to 

 their habits, and we have therefore thought it best to rewrite 

 their life history, including such portions of our former paper 

 as would serve our purpose. They are both slender-waisted black 

 wasps, albopilosum having bunches of snowy white hairs on 

 the first legs, and measuring three-quarters of an inch in length, 

 while ruh^ocinctum is a little smaller, and, as the name implies, 

 wears a red girdle. 



Although these wasps are called wood-borers they will use 

 convenient cavities in any material. When we went out to our 

 summer cottage, in the last days of June, 1895, we found many 

 little wasps of the species Trypoxylon riihrocinctum busily work- 

 ing about a brick smoke-house on the place. Closer examina- 

 tion showed that in the mortar between the bricks were many 

 little openings leading back for a considerable distance, which 

 were occupied by the wasps. It would seem that these holes 

 were excavated by some other agency than the wasps themselves 

 as they were so much too deep for their purposes that before 

 using them they built a mud partition across the opening about 

 an inch from the outside of the wall. Later on we found nests 

 ■of the same species in the posts which support an upper balcony 



♦Psyche, Nov., 1895, pp. 303-306. 



