264 
Psyche 
[September 
cate movements and displacements of prey, whereas dashed lines 
with arrows indicate movements and displacements of wasp. 
Basic sequence involves detection — by scent (a) or by sight (f) 
or both, — attack of prey and escape of it — by jumping (b) or 
running (g). It generally ends with capture of prey (c) and is 
followed by stinging which is not represented here (see Steiner, 
1962). Attempt at capture might also trigger less typical responses 
such as those represented in figures h, i, j. 
Detection by scent, scent tracking is represented on Plate 22, 
figure a. The wasp walks slowly, head down with the antennae 
tapping the soil. Information picked up may be chemical or chemo- 
tactile. The wasp, like a hunting dog, follows with great precision 
the scent trails left by crickets and investigates droppings. 
Detection by sight is represented on Plate 22, figure f. The wasp 
generally walks quickly in an apparent haphazard and irregular way, 
frequently changes direction, or flies short distances. The wasp does 
not walk “head down” nor are the antennae tapping the soil. En- 
counter of crickets is mostly unpredictable, except if the wasp has 
been guided toward favorable areas by memory of previous hunting 
trips. Movements and displacements of encountered crickets facilitate 
detection by sight (see PL 22, g). 
Detection of prey seems to have important activating effects on 
the subsequent hunting behavior of the wasp. However, the relative 
importance, role and possible order of succession of the two methods 
of detection in the behavior of the wasp are unknown. According 
to Tinbergen (1935) hunting in another sphecid, the bee wolf 
(Philanthus triangulum Fabr.), involves a unidirectional succession 
of sight-scent detection. The two methods of detection are compared 
in Table 2. 
In full hunting phase, detection of the cricket is almost invariably 
followed by attack (pouncing) and pursuit of the escaping cricket. 
The behavior of the escaping cricket is variable and unpredictable. 
Running away (see PL 22, g) is frequent, but the cricket might 
jump away (see PL 22, b), stop suddenly under or behind a nearby 
obstacle, enter a burrow, or change direction. 
Therefore, disruption of pursuit is frequent. Typically the wasp 
instantly stops running and stands upright in a characteristic head up 
posture with the fore legs stretched to the maximum (see Plate 22, d). 
The antennae, often vibrating, are held in a special manner. Left 
and right side movements of the body and often of the head are 
also performed in quick succession (see arrows on figs, d and e, 
PL 22). Fast visual scanning and exploration of the surroundings 
