OBSERVATIONS OF THE NESTING BEHAVIOR 
OF RUBRIC A SURINAMENSIS (DEGEER) 
(HYMENOPTERA, SPHECIDAE) 
By H. E. Evans, 1 R. W. Matthews, 2 and E. McC. Callan 3 
Introduction 
Rubric a surinamensis (DeGeer) is one of the most familiar and 
well-studied digger wasps of South America. Yet the published 
accounts of its nesting behavior present a number of puzzling fea- 
tures. For example, Brethes (1902) and Llano (1959) reported 
that females clean the cells of uneaten parts of flies and other debris, 
but others have not confirmed this. There are many records of 
females preying upon flies, but Callan (1950) has reported the 
occasional use of Lepidoptera and Odonata, a striking exception to 
the usual prey constancy of solitary wasps. Also Brethes (1902) 
reported that the cocoons contain only two pores, although other 
Bembicini in this size range make 5-10 pores per cocoon. A fuller 
summary of published observations has been presented by Evans 
(1966). 
In the hope of clarifying these and other problems relating to this 
widely distributed and apparently very successful species, the three 
of us have pooled our notes on three widely separated populations. 
One of us (EMC) resided in Trinidad for several years, and had 
an opportunity to observe a nesting aggregation in the hard, sandy 
driveway of his house near the Imperial College of Tropical Agri- 
culture at St. Augustine, a residential area about 13 km east of Port 
of Spain. Two of us (HEE and RWM) visited Colombia and 
Argentina in January and February, 1972, and encountered the 
species in some abundance in both countries. Studies in Colombia 
were conducted on a large aggregation in a hard, gravel road on a 
denuded and eroded hillside just west of the city of Cali. In Argen- 
tina, we found three smaller aggregations in diverse situations within 
one day’s drive of the city of Tucuman. Thus if any of the puzzling 
features of the behavior of this species bear a relationship to geog- 
department of Zoology and Entomology, Colorado State University, Fort 
Collins, Colorado 80521. 
department of Entomology, University of Georgia, Athens, Georgia 
30602. 
division of Entomology, C.S.I.R.O., Canberra, A.C.T., Australia. 
Manuscript received by the editor August 13, 1974. 
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