LIBRARY

698
COLLEGE ENTOMOLOGY
boreal North America. In California the trapdoor spider wasp, P. plantus
(Fox), provisions its nests with the large trapdoor spider, Bothriocyrtum
californicum (Cambridge).
Among the most conspicuous wasps are the tarantula hawks, members of the
genus Pepsis Fab. They are large species from 20-40 mm. in length, metallic
blue-black and with infuscated, violaceous, orange, or fiery-red wings, and they
provision their nests wit.h spiders, trapdoor spiders, and tarantulas. P. elegans
Fab., a rather small species, is the eastern representative of this genus in North
America while a number occur in the south and
southwest. In the latter areas P. formosa (Say),
20-40 mm., is the commonest and largest species
with red wings and P. obliquerugosa Lucas,
30-40 mm., the largest all-blue species. Other
genera include the European Agenia Dahlbom,
Pseudagenia Kohl, Priocnemis Schii:idte; the
Indo-Australian Aporus Spinola and Salius
Fab.; and the American and Oriental Ceropales
Latr. whose members live as inquilines in the
nests of species of Psammochares and share the
food of t.he host larva:.
FIG. 248. Worker of the common
yellowiac\cet, VesplIla pennsylvanica
(Saussure), a groundnesting
species. (From Inserts oj
Western North America.)
Family VESPIDlE (Leach 1816) Stephens 1829
(Ves'pi-dee, from the Latin vespa, a wasp).
Paper Wasps, Yellowjackets, Hornets.
Medium-sized to large, mostly slender,
smooth, pubescent or hairy, yellow and red
with black or brown markings and bands; vary­
ing in size from 9-17 mm. Head transverse and as wide as the thorax; c1ypeus
well developed; ocular malar spaces (areas between bases of mandibles and
lower margins of eyes) short or scutellum
long; mandibles strong, dentate.
Antenna: fairly long and slender;
only slightly bowed. Thorax
nearly as wide as abdomen;
metepisternum without dorsal
anterior plate. Legs strong;
middle tibire two-spurred; claws
simple. Wings long and narrow;
folded longitudinally in repose;
hind pair without anal
lobe; veins not extending to the
apical margins; fore pair with
I I
I I I
I I coxa 1 I prepeclus
! laps. 1
pronotuln
FIG. 249. Thorax of Polisies aurifer Saussure showing
important parts.
three submarginal cells. Abdomen sessile, somewhat conical, usually marked
with transverse dorsal bands; sting well developed and effectivej male genitalia
used in separating the family into at least three natural groups.