94 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



of greater size than the prey, and the food sources of the adults and 

 immature stages are frequently the same. 



It is apparent, as Clausen and other writers have pointed out, that 

 there are instances of a particular species showing characteristics 

 which fit both the definitions for predator and parasite. Thus, among 

 the evaniids one wasp larva destroys all the eggs in an ootheca, but 

 in spite of this the larva has more of the characteristics of a parasite 

 than of a predator ; the adult wasp does not utilize the same food as 

 the larva (adults have been taken on flowers and on honey dew from 

 scale insects). It is questionable whether the evaniid larva kills the 

 cockroach egg outright. The wasp larva, being restricted to the inside 

 of the ootheca, is not free-living. Probably the only criterion by which 

 the evaniid could be judged to be a predator, by Clausen's definition, 

 is that more than a single egg is devoured by the maturing wasp larva. 



Among the other wasp parasites (Encyrtidae, Eulophidae, Eupelmi- 

 dae) of cockroach eggs many individuals develop in a single ootheca. 

 When a hundred or more wasps emerge from an ootheca which con- 

 tained less than 20 eggs, it is obvious that a single cockroach egg sup- 

 ported more than one wasp, yet it is possible that one particular wasp 

 larva may have fed upon more than one cockroach egg before be- 

 coming an adult. We consider all entomophagous wasps that develop 

 in cockroach oothecae to be parasites rather than predators. 



On the other hand, even though Anastatus floridanus, A. tenuipes, 

 and Tetrastichus hagenowii are egg parasites as larvae, the adult 

 females are, in a sense, predators when they sometimes eat part of the 

 cockroach egg that oozes through the oviposition puncture (Roth and 

 Willis, 1954a, 1954b). Williams (1929) has seen the female of 

 Ampulex canalicidata imbibe blood that oozed from the cut ends of 

 the cockroach's antennae after she had clipped them off before leading 

 the prey to her nest. Yet despite this evident predatism on the part 

 of the adult, the larva feeds as a parasite on the stored cockroaches 

 in accordance with Sweetman's (1936) (though not Clausen's 1940) 

 definition of parasitism, which is "that form of symbiosis in which one 

 symbiont lives in or on the host organism and feeds at its expense 

 during the whole of either the immature or mature feeding stage." 

 The ampulicid larva, as the evaniid, is not free-living and does not 

 kill the host immediately by direct attack, even though it may require 

 more than one victim to reach maturity. Thus, within one individual 

 both parasitic and predatory behavior are operant during different 

 stages of its life history. 



With the above discussion in mind we have summarized below the 

 various biotic associations of cockroaches. Only a few examples are 



