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Division PARASITICA 



By Paul M. Marsh and Robert W. Carlson 



The divisional name applies to those groups of nonsocial Apocrita in which the ovipositor al- 

 ways retains the function of egg placement (i.e. is never modified to be only a stinging organ) 

 and in which the species: (1) are usually ectoparasites or endoparasites of other insects or 

 spiders, and, less frequently, phytophagous; (2) are never provisioners of nests; and (3) are 

 mostly incapable of stinging human beings. The latter fact appears to result largely from the 

 relative smallness of most Parasitica; they generally are not physically capable of piercing the 

 human epidermis with the ovipositor. However, collectors of Ichneumonidae know by experience 

 that a significant proportion of the species above median ichneumonid size are capable of sting- 

 ing humans. Whether any Parasitica of families other than Ichneumonidae are capable of sting- 

 ing humans is unknown to us, but it seems likely that a few of the largest Braconidae would 

 have this capability. Probably all or nearly all females of Parasitica, when grasped in ways that 

 do not restrict abdominal movement, make reflexive stinging movememts; similar defensive 

 movements are also made by males of at least some species. Some of the ectoparasitic members 

 of this division have stings which paralyze the host permanently, and the stings of ectoparasitic 

 species in general are more venemous than those of endoparasitic species (see Iwata, 1976). 

 However, there are presumably numerous species of both types which do not have venemous 

 stings. 



The dividing point between the divisions Parasitica and Aculeata is rendered arbitrary by the 

 fact that the latter includes numerous ectoparasitic species (but no endoparasitic ones) as well as 

 by the fact that there are no differences in biology or structure which apply to all the members 

 of either group. Recognition of the two groups is a matter of tradition and convenience. 



The habits and life histories of Parasitica are too diverse to be delved into here. Limited 

 discussions will be found in the introductions for some of the genera and supergeneric taxa. 



Biology: Clausen, 1940. Entomophagous Insects, p. 3-342. — Doutt, 1959. Ann. Rev. Ent. 

 4:161-182. — Hagen, 1964. In DeBach, Biol. Control Insect Pests and Weeds, p. 168-246. 

 —Askew, 1971. Parasitic Insects, p. 113-184. —Iwata, 1976. Evol. Instinct, Compar. Ethol. 

 Hym., Eng. ed., p. 1-84. 



