2 
Psyche 
[Vol. 88 
mantis, etc.). Counter-attacks by such prey and occasional killing of 
the predator have even been reported (e.g., Deleurance 1941, pp. 
287-288, for a praying mantis attacked by the sphecid wasp Stizus 
distinguendus; also 1945, p. 29 for Tachysphex costai Dest.). Dead 
spider wasps have also been found in spider webs in natural 
conditions (pers. obs.). Non-predaceous prey can also exhibit 
defense reactions, however, as shown before for crickets attacked by 
Liris nigra wasps (Steiner 1968). 
The anti-predator system of acridid grasshoppers is now de- 
scribed, analyzed, as observed both in nature and captivity (sum- 
marized in Steiner 1976). The prey are: (1) mainly adult or subadult 
Oedipodinae, but also a few Cyrtacanthacridinae, all attacked by 
the sphecid wasp Prionyx parkeri Bohart and Menke, (2) to a much 
lesser extent smaller, earlier, instars preyed upon by Tachysphex 
wasps (details in next section). For the latter prey, defense reactions 
were essentially the same, except for the ones involving the wings, 
undeveloped at these stages. Prey hunting and stinging by Prionyx 
parkeri are described in detail in Steiner 1981 (in press). 
Materials and Methods 
Field observations 
Prionyx parkeri wasps were observed mainly in the grassland 
desert and adjacent riparian habitat of S.E. Arizona, U.S.A., at the 
foot of the Chiricahua Mountains, East of Willcox, during the 
summer of 1972. 
Observations in captivity 
Individually marked Prionyx parkeri and Tachysphex [mostly 
tarsatus (Say)] wasps were observed in controlled laboratory units 
about 60 X 50 X 50 cm (general method described in Steiner 1965): 
(1) at the Southwestern Research Station, Portal, Arizona, during 
the sprng and part of -the summer 1973 (= Arizona study); (2) in 
central Oregon, U.S.A., near Bend, using a field trailer, during the 
summer of 1977 (= Oregon study). The following acridid grass- 
hoppers taken from the wasps’ habitats were used in the Arizona 
study; (1) for P. parkeri, adult or last instar nymphs of: Oedipodi- 
nae, mostly Trimerotropis pallidipennis p. (Burm.), also Conozoa 
carinata Rehn, a few Cibolacris parviceps (Walker) — Cyrtacan- 
thacridinae, a few Psoloessa delicatula Scudder and an occasional 
