12 
Psyche 
[Vol. 88 
usually seize the wing base(s) or abdomen rather than one hind leg 
(Fig. 1). Hind legs of crickets, grasshoppers, sometimes phasmids, 
often covered with strong spines, are one of their major systems of 
escape and/or defense. Some wingless phasmids can jab the spines 
into an aggressor (Robinson 1968b). Overt defense by kicking has 
also been described in some large aphids (in Edmunds 1974, p. 245) 
and in a number of orthopterans such as crickets (Steiner 1968) and 
Locusta migratoria for instance (Parker et al. 1974). In the latter 
case it can be so violent that the attacker is knocked 20-30 cm away. 
According to Parker et al. (1974) hind leg raising often precedes 
kicking (threat?). It is also part of the defense postures of male L. 
migratoria, the giant weta ( Deinacrida ) of New Zealand (in Sebeok 
1977, Fig. 5a, p. 342) and mormon crickets when attacked by the 
digger wasp Pa/modes laeviventris (Parker and Mabee 1928, p. 9). 
In the latter case, as in Prionyx and Tachysphex, the wasps 
succeeded in stinging only with considerable difficulty. In the 
present study hind legs were often raised past the vertical line (Fig. 
5e) and even as far forward as the level of the head, as in Fig. 1 for 
instance, in addition to tail or body raising. This was also observed 
once in response to an approaching Tachysphex tarsatus. Freezing 
into such postures made access to the dorsal area and wasp 
posturing very difficult, sometimes impossible (Fig. 5e) (obstructive 
behavior) and the efficiency of this behavior appeared even to 
increase as a result of repeated attacks. Interposition of legs 
(obstruction behavior) was also observed in mole crickets attacked 
by Larra wasps (Williams 1928). 
Brushing and pushing away (Figs. 1 and 5f) are more difficult to 
evaluate since they are more graded and variable responses which 
are not easy to detect, let alone quantify, in the confusion of the 
attack. Plausibly these responses work best (if at all) at early stages 
of contact with the wasp, also if the prey is very large and vigorous 
or if the wasp is more likely to easily give up, for instance at early 
stages of hunting (Steiner 1976). It is doubtful that a firmly 
anchored wasp can easily be dislodged in this way. 
[Remark: some orthopterans extend or raise their fore legs, 
vertically, as part of a threat-intimidation posture (e.g., Neobarettia: 
Cohn, in Sebeok 1977, p. 342, Fig. 5b)]. 
Orthopteran hind legs are often given special attention and are 
paralyzed first by some predatory waps such as Liris and Tachy- 
sphex (Steiner 1962, 1976). Prionyx wasps can give priority to the 
