THE NESTING BEHAVIOR AND 
LARVAL MORPHOLOGY OF PISON KOREENSE 
(RADOSZKOWSKI) (HYMENOPTERA: SPHECIDAE)* 
By Joseph K. Sheldon 
Department of Entomology, University of Illinois 
Introduction 
The genus Pison has a wide distribution, occurring in most tropi- 
cal countries and extending into the temperate zones. Turner (1916) 
lists 50 species occurring in Australia, 17 in the Austro-Malayan 
Region, 13 in the Oriental Region, nine in the Palearctic Region, 
nine in the Ethiopian Region, and eleven species from the Americas. 
The only native species in the U. S. or Canada is apparently P. 
laeve Smith, reported from Georgia (Krombein, 1951). 
Pison koreense , a native of Korea, China, and Japan, was apparent- 
ly introduced into this country after World War II (Krombein, 
1958). At the time of Krombein’s publication it had been collected 
from two localities: McLean, Virginia in 1954, and Palisades Park, 
Illinois in 1957. Since that time it has been reported from Plum- 
mers Island, Maryland, and from Michigan (Krombein, 1967). 
Adults of P. koreense are small, black wasps having a wing span of 
about 10 mm, and may be distinguished from our native sphecoid 
wasps by their two submarginal cells and reniform eyes which are 
covered with short dense hairs. 
The present study was carried out in east-central Illinois. In- 
formation on the nesting behavior and larval morphology of P. 
koreense is presented, and some obvious differences between this spe- 
cies and other members of the genus are noted. 
General Ecology 
Activity and nest habitat — Pison koreense was found nesting 
at two localities in east-central Illinois: in a culvert at Kickapoo 
State Park and under a bridge one mile east of Urbana. Apparently 
there is a univoltine life cycle with the adults emerging near the 
end of July, although additional collecting needs to be done to sub- 
stantiate this. The wasps are active for only a few weeks and most 
are gone by the end of August. Krombein (1958) reported that 
the cells collected by A. D. Cushman at MLLean, Virginia, were 
found inside a photographic tank which was stored under an old 
* Manuscript received by the editor June 4-, 1968 
107 
