150 
Psyche 
[September 
BIOLOGICAL NOTES ON SPHEX WRIGHTII 
(CRESSON) 
By Charles H. Hicks 
University of Colorado 
The digger wasp, Sphex wrightii (Cresson), is one of the 
smallest Sphecids I have yet had an opportunity to study. 
It was placed in the genus Colopteru by Cresson in 1868. 
Professor H. T. Fernald has kindly determined this species 1 
for me and gives an account of it in his recent monograph 
of wasps of the genus Sphex. 2 My study is based on obser- 
vations made on the habits and nesting of the female since 
the male was not taken at all. The wasp was found only 
rarely at Owens Lake, near Boulder, in August, 1933, al- 
though its small size and somewhat concealed hunting hab- 
its may have caused this scarcity to appear more evident 
than actual numbers would warrant. Specimens were seen 
on different days, hunting among the tumble weeds. Two 
nests were taken : one, on August 4th ; the other, a week 
later. 
The nest of August 11th and the wasp’s activity at the 
time appear more complete and possibly more typical than 
the earlier record and are given, in part, below. The pres- 
ence of the nesting wasp was noted by means of a rather 
loud buzzing the digger made while she was excavating 
along a road in a field near the lake. She was found at 1 :37 
P. M. and observed continuously until the nest was finished 
and the wasp captured at 2:19. When first found, she had 
barely begun her vertical tunnel, but was already carrying 
*Dr. T. D. A. Cockerell examined one specimen and likewise ascribed 
it to this same species. The writer is pleased to acknowledge this 
favor. 
2 For a consideration of this species and other Digger wasps of the 
genus Sphex, see the paper by Professor Fernald entitled “The North 
American and West Indian Digger Wasps of the Genus Sphex (Am- 
mophila auct.).” E. 0. Painter Printing Co., Deland, Florida, pp. 
1-167. Plates I & II. Figs. 1-39. 1934. 
