6 
Psyche 
[Vol. 88 
using their powerful spinose legs, terminal claws, and also mandi- 
bles. These wasps tightly “embrace” the grasshopper, in an anti- 
parallel posture and strongly cling to them (Fig. 1). In contrast, 
many larrine wasps (e.g. Liris, Tachysphex ) are comparatively frail, 
short-legged, and cannot physically overpower their prey as success- 
fully as Prionyx wasps do. Their prey often struggles free, in 
contrast to Prionyx prey which seldom succeed, after the “embrac- 
ing” stage, in spite of frantic efforts to kick and / or brush, push away 
the attacker with the powerful hind legs. Prionyx prey also try to 
deny free access of the wasp to the dorsal side by raising their long, 
folded, hind legs, often beyond the vertical, headwards (hind leg 
raising: Fig. 5e). Powerful kicks (Fig. 5e) sometimes send the wasp a 
few cm from the grasshopper, but this works mostly before the wasp 
can secure a firm grip. Pushing action with the tarsi of the powerful 
hind legs can also be recorded. They are very precisely directed at 
the points seized by the wasp as shown in Fig. 1 . In the latter, drawn 
from a photograph, the grasshopper tries, with its right hind leg, to 
push away the left front leg of the wasp while it attempts, with the 
left hind leg, to exercise strong pressure on the head, jaws, of the 
attacker and presumably get the wasp to release its mandibular grip 
(in Fig. 5f these “points of pressure” have been circled). Wing 
fluttering and even flying attempts can also be observed in reponse 
to the grasping action of the wasp. The orthopteran also performs 
snapping motions with the jaws but is seldom able to bite the wasp. 
The very globulous abdomen of Prionyx wasps appears to be 
especially well adapted to prevent such biting. The abdomen is 
particularly exposed since the wasp delivers the first sting in the 
throat of the prey, dangerously close to the powerful jaws (Fig. 5g). 
Chemical defenses: regurgitated fluid (Fig. 2) 
In addition and often as a last ditch defense the grasshopper 
regurgitates through the mouth a large drop of dark fluid (“tobacco 
juice”) that usually spreads rapidly over the body areas closest to the 
mouth, ventrally, namely the thoracic surface (Fig. 2). This surface 
sometimes becomes completely covered with the substance. From 
there it can spread to other body areas, if struggling is intense 
enough. On Fig. 1 one drop can be seen on the right antenna of the 
grasshopper and one on the tibia of the right hind leg (arrows). 
