PSYCHE 
VOL. XXXIV. DECEMBER 1927 No. 6 
PARASITES AND HABITS OF DIANTHIDIUM PUDICUM 
CRESSON 
Charles H. Hicks, 
University of Colorado. 
The habits of Dianthidium pudicum Cresson 1 have not 
previously been known, as far as it can be learned from a review 
of the literature. The following account is based on studies of 
the species, at or near Boulder, Colorado. 
D. pudicum builds cells of pebbles and resin, placing them 
in depressions or attaching them to the sides of rocks, in fields 
and open places. Nests of this bee were first taken in the fall of 
1925. Many have, since been. found at all seasons and, during 
the summer of 1926, observations w T ere made on the constructing 
and provisioning of a nest. 
Cells have been taken from the stones, brought to the labo- 
ratory where they were kept at room temperature, and the 
insects reared. In this way a number of bees and several par- 
asites have been obtained. 
From a nest secured April 11, 1926 at East Boulder, a male 
and female parasitic wasp ,Eusapyga proxima Cresson 2 , emerged 
on May 12, 1926; a female wasp May 14; a male D. pudicum 
May 18; and a male wasp on May 21. Specimens of E. proxima 
have emerged from some other nests of D. pudicum and always 
from the cocoon of the latter insect. This fact shows that the 
parasite lives on the tissues of the young bee larva or pupa and 
does not early crowd it out, using its food, as do certain bees 
living in the cells of other bees (e. g. Stelis sexmaculata on Al- 
cidamea producta) 3 . 
kindly determined by Professor T. D. A. Cockerell. 
2 This wasp has been determined by Mr. S. A. Rohwer. 
3 Reported by Graenicher, 1905. 
