i 3 4 WASP STUDIES AFIELD 



Trypoxylon tridentatum Pack. [S. A. Rohwer.] 



A burrow in the pith-chamber of a certain elder twig 

 at Lake View, Kansas, must surely have been an attractive 

 resort although inconspicuous to us for it had evidently 

 been used twice as the cozy domicile of insects. 



The burrow in the twig was six and one-half inches in 

 total length. It had evidently been made and used by an- 

 other insect previous to the present one, for the lower three 

 and a half inches was tightly packed with debris of the 

 former tenant. At that point a mud plug was firmly fitted in 

 to wall up this refuse. A little way above this was another 

 mud partition making a cell three-fourths inch long, and a 

 third plug was inserted to make another such room. There 

 may formerly have been more cells we do not know for a 

 mowing machine had cut the stalk off smoothly just above 

 this point, leaving the gallery open. The neat little cells 

 contained tiny cocoons. It was brought in from the field on 

 August i, and on August 15 an adult T. tridentatum 

 emerged. 



Although this species was described in 1867, no liter- 

 ature could be found on the biology of this wasp. 



Silaon niger 1 Roh. [S. A. Rohwer]. 



An elder stem with a little hole in the top aroused our 

 curiosity. On opening it we found, in the pith-chamber, 

 some small pellets of mud, a few bits of dried leaves thrown 

 in promiscuously, and then long partitions with four co- 

 coons at intervals among the debris of dried leaves, little 

 pieces of mud, small stones and little pellets of" excrement. 



1 This belongs to the family Larridae, and is the same as Niteliopsis 

 in Fox's and Williams' articles, fide Rohwer. 



