Numbers
Nearctica.com lists 15 North American species in
Pepsis and four in
Hemipepsis.
Arnett (pp. 591-592) four subgenera: Pepsis (6 spp.), Stenopepsis (1 sp.), Dinopepsis (2 spp.), Gigantopepsis (3 spp.), unassigned (6 spp.). Describes
Pepsis (Dinopepsis) formosa. He lists Hemipepsis (4 spp.) with no description.
(1)Size
14-40 (50?) mm (some species very large)
Identification
Large blue-black wasps, most with orange wings. Some species have orange antennae. Females have curled antennae, males straight.
Among the largest and most easily recognized genera of spider wasps, only Hemipepsis is easily confused, but orange-winged individuals of Entypus are superficially similar. This genus can be recognized by the characters given below:
Large size 40 mm+. With blue, blue-green, or blue-violet iridescence. Only rarely does Hemipepsis have iridescence and most in that genus lack it completely, or if it is present it is very vague. Only rarely does Entypus reach the size listed above.
Wing ventaion is very important for identification of Pepsis especially distinction between Pepsis and Hemipepsis. Those characters are as follows:
-Marginal cell apically separated from the costal margin, making that cell appear
very rounded.
-First recurrent vein meeting the second submarginal cell at its basal one-third,
thus making the first discoidal cell rather short and rounded. In Hemipepsis
the first recurrent vein meets the second submarginal cell at its apical one-third
or is occasionally interstitial with the second transervse cubital vein, thus making
the first discoidal cell rather long and pointed.
-Subcircular irregularity at the base of the first discoidal cell not as developed
as in Hemipepsis.
Pulvillar pad and comb in Pepsis is rather weak, the pulvillar pad about half as wide as the apical tarsal segment. The pulvillar comb consists of eight to ten weak setulae. In Hemipepsis this character is well developed with a large pulvillar pad that is approximately three-quarters the width of the apical tarsal segment and the puvillar comb that consists of 14-40 strong setulae.
The number of species of Hemipepsis is limited (four nearctic) but there are near 20 species of Pepsis, most with a range that encompasses a majority of the southwestern United States. It is often possible to identify Hemipepsis from photographs to species. This is not the case with Pepsis. Although it is often possible to narrow down the choices to groups of similar species, it is often impossible to assign a species name with that degree of certainty. An extensive knowledge of local fauna helps, as well as extensive work with museum specimens. Despite the large size of members of this genus many photographs must remain identified, as some of the species are very similar.
Range
Most species in southwestern United States. Only one species, Pepsis elegans, in east. Genus occurs south into neotropics
Food
Adults take nectar, and are particularly fond of milkweed--Asclepias.
Life Cycle
Mating takes place on flowers, or sometimes near a "hilltop", such as a large cactus, defended by the male. Females seek out tarantula burrows, paralyze them, and bury it in a burrow, laying a single egg. Larvae feed on the paralyzed spider.
Remarks
Genera
Pepsis and
Hemipepsis have identical biology and are not distinguishable in the field. They are discussed here together under
Pepsis, though there is a brief
account for
Hemipepsis.
These wasps are reputed to have a very powerful sting, though they are not agressive.
See Also
Hemipepsis, also
Entypus, a related genus of large Spider Wasps.
Print References
Arnett describes genus, pp. 591-592.
(1)
Arnett and Jacques illustrate
Pepsis formosa, #287
(2)
Milne has photo of
Hemipepsis sp. #458, description p. 839
(3)
Swann and Papp, description p. 546, illustrations, color plate 7k--
Pepsis mildei, fig. 1190--
Pepsis formosa (4)
Drees, fig. 333--photo of
Pepsis sp., description p. 277
(5)
Powell, plate 16f--
Pepsis sp., description p. 336,
(6)
Werner gives description and line drawing, p. 126
(7)
Salsbury, p. 280--photo of
Pepsis formosa from Kansas
(8)
Alcock, p. 29, describes mating behavior of Hemipepsis ustulata.
(9)
Salsbury, p. 280--photo of
Pepsis formosa from Kansas
(8)
Hurd, Paul, 1952.
Revision of the Neartic Species of the Pompilid Genus Pepsis. AMNH Bulletin, 98(4). (Reference from
Jeff Hollenbeck.)
