146 
Psyche 
[December 
THE GENUS LITHURGUS (HYMENOPTERA: 
MEGACHILIDiE) 1 
By Theodore B. Mitchell 
North Carolina State College 
Although the genus Lithurgus is widely distributed over 
the earth, the number of species it includes is small, and in 
no part of the world is there any great number of them 
known to occur. In North America there are four distinct 
species, while from all Central and South America only 
about fourteen species have been described. Since the group 
is so limited, it is only rarely that new forms are discovered, 
and the few that are known have not as yet been keyed out 
in the literature. This paper is a brief summary of the 
genus in North America, together with a few records and 
descriptions from other regions. 
The following key separates the known Nearctic species 
together with an apparently new species from an island off 
the west coast of Mexico 
1. Females (only six abdominal terga visible, the sixth 
entirely hidden by extremely dense pubescence) 2. 
Males (seven abdominal terga visible, the apical terga 
visible through the relatively thin pubescence) 7. 
2. Facial protuberance much narrower than width of 
face 3. 
Facial protuberance almost as broad as face 5. 
3. Facial protuberance entire, protruding uniformly for 
its entire width, slightly bowed gibbosus Smith 
Facial protuberance not entire 4. 
4. Margin of prothorax dorsally conspicuously fasciate; 
scopa white echinocacti Cockerell 
1 Research Contribution No. 2 published with the aid of the State 
College Research Fund, Department of Zoology, North Carolina 
State College of Agriculture and Engineering of the University of 
North Carolina. 
