■J2 GENERA ol HYMENOPTERA. 



PARASITICA. 



Til is \orv extensive series eoinjjrises some of the largest families 

 of till' Onlii-, the iiicinlH'rs (if which in their hirvu state, excej)tin_a' 

 the gall-feeding Cynipidae, are ])arasitic upon or within the bodies of 

 other insects, and, nsiiii;- the words of Westwood, "are of vast impor- 

 tance in the economy of nature by preventing the too great increase 

 i)f (hrterent sjiecies of insects, es])ecially of the cater])illars and moths, 

 of which they destroy a great number." The series is characterized 

 cliietly by having the abdomen attached to the apex of the thorax 

 liy a pnrtinii (tidv, generally a verv small ]iiirtinii, of its transverse 

 iliameter, ilie first segment being often very slender at base, i.e. petio- 

 late, and by the ovipositor being elongate and ])lurivalve, .somewhat 

 similar in form to that of the preceding series. Apterous forms occur 

 rarely in all tlie large families, but their cliaracters are not sufficiently 

 well known to tabulate satisfactorily. 



The distinguishing characters of the eight families into which the 

 series is divided are repeated here for convenience : 



Table of Families. 



Anterior wings with seycral closed cells, or at least a closed or nearly closed iiiar- 

 };iiial or sijhniarKinal cell, very rarely without either as in Jfyplin in 



l^vaiiiidie and a few genera of Kraconidae® 2. 



Anterior wings almost veinless and witliont cells, rarely with a closed marginal 

 or siihmargiiial cell, as in some genera of Proctotrupidief 7. 



* In a few Proctotrui)id genera (e.g. ChelogymirS, Embolemns. etc.) the anterior 

 wings exhibit a closed marginal or siibmarginal cell or both, and closely resemble 

 the Uraconidic in having a distinct recurrent nervure; they may, however, be 

 distinguishe(l frum the families in this category as follows : from the Cynipidse 

 l)y tln^ distinct costal nervure and stigma: from the I'lvaniidie by the mode of 

 the insertion ol' the abdomen ; from the Trigonali(he and h-hiieumoniihe by the 

 aniiiiiia- having less than 16 joints :ind the al)seuce of the second recurrent ner- 

 vure. and from the Ste])hanida' and P.racoiiida' by the jiosterior wings being dis- 

 tinctly lobed at base, excej)! the genus i/c/onts, which, however, is readily dis- 

 tinguished by the curious neuration as described in its place in the Proctotrupidae. 



t III Ihipiin, in ICvaniidie. and some of the genera of Aphidiina-, in IJraconidiP, 

 the anterior wings are without closed marginal, siibmarginal or discoidal cells ; but 

 ill the former the abdomen is inserted on the disk of the melathorax, and in the 

 hitter the stigma is lanceulute or triangular and well developed, the posterior 

 wings not lobed at base, the median and sonietiines the submedian cell is closed, 

 and tlu! altdominal segments are loosely articulated and capable of being beut 

 beneath the thora.x. In some genera of Cyuipida; the anterior wings are also 



