10 
Psyche 
[Vol. 88 
reactions, their degree of predator-specificity. Comparisons are 
made with other orthopterans, with similar and different anti- 
predator strategies. Effectiveness, always difficult to prove, particu- 
larly when attacks or lack thereof depend on the internal state of the 
predator like in the present case, will be assessed rather than 
analyzed mathematically. 
All defenses described before (except crypticity) are secondary 
rather than primary defenses since they are exhibited during 
encounters (Edmunds 1974, pp. 1, 136). Defenses are often anti- 
location, anti-capture or anti-consumption devices (i.e. Alcock 
1975, p. 333). Furthermore, many species have several lines of 
defense (integrated defense systems: Edmunds 1974, p. 243). Thus 
the mantid Polyspilota aeruginosa may run, fly, give a startle 
display, slash at the attacker. It can also feign death if persistently 
handled in a rough way. It soon recovers, however. The brightly 
colored abdomen might also represent flash behavior (in Edmunds 
1974, p. 245). Each aspect of the defense system will now be 
discussed separately. 
Escape by jumping, flying away 
This is a classical and common case of sudden startling (flash or 
deimatic behavior Fig. 5b) followed by sudden disappearance into 
crypsis (landing; Fig. 5c) (Edmunds 1974, pp. 146-148) by using 
protective colors (e.g. Isely 1938). This is usually a very efficient 
mechanism but Prionyx wasps occasionally dash at flying grass- 
hoppers (Fig. 5b), even sting them in mid air, or take them by 
surprise before they can escape. Pygmy mole crickets that escape by 
flying away are also grasped and/or stung during flight by the 
sphecid wasp Tachytes mergus (Yoshimoto, in Krombein and 
Kurczewski 1963, p. 147) and also by Tachytes minutus (Kurczewski 
1966). This defense is not especially aimed at digger wasp predators. 
Detection of the predator is probably visual but could also be 
based on hairs sensitive to airborne vibrations, as in some caterpil- 
lars such as Barathra brassicae (Tautz and Markl 1978). 
Use of hind legs other than for jumping: kicking or obstructive 
behavior such as hind leg raising or interpositions, brushing 
away, pushing away 
Hind leg autotomy used by crickets (Steiner 1968) was never 
observed in grasshoppers in the present study but Prionyx wasps 
