^ 



22 GENERA OF HYMENOITERA. 



PARASITICA. 



Thifj very extensive series comprises some of the largest families 

 of the Order, the members of whieh in their larva state, excepting 

 the gall-feeding (;vnii)i(laB, are panisitic ui)on or within the bodies (jf 

 other insect"!, and, using the words of WestwotKl, "are of vast impor- 

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

 of different s|)ecies of insects, esjx?cially of the caterpillars and moths, 

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

 chiefly by having the abdomen attached to the ajiex of the thorax 

 by a jjortion only, generally a v^ery small portion, of its transverse 

 diameter, the first segment being often very slender at base, i.e. petio- 

 late, an<l by the ovipositor being elongate and plurivalve, somewhat 

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

 rarely in all the large families, but their characters are not sufficiently 

 well known to tabulate satisfactorily. 



The distinguishing characters of the eight familias into which the 

 series is divided are repeated here for convenience : 



Table of Families. 



Anterior wings with several closed cells, or at least a closed or nearly closed mar- 

 gitial or sulmiiirjiinal cell, very nirely without either as in Hyptin in 

 Evaniidie ami a few genera of Hracoiiidie''- 2. 



Anterior wings almost veinless and without cells, rarely with a closed marginal 

 or submarginal cell, as in some genera of Proctotrupidajf 7. 



* In a few Proctotrupid genera (e.g. Chelugynus, Embolemus, etc.) the anterior 

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

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

 distinguished from the families in this category as follows : from the Cynipidse 

 by the distinct costal nervure and stigma; from the Evaniidie by the nutde of 

 the insertion of the abdomen ; from the Trigonalidse and Ichneumonida^ by the 

 autenuie having less than l(i Joints and the absence of the second recurrent ner- 

 vure. and from the Stephanida' and Bracotiida; by the posterior wings being dis- 

 tinctly lohed at l)ase, except the genus Helorus, which, however, is readily dis- 

 tinguished by the curious ueuration as described in its place in the Proctotru]iid8e. 



t In Ht/ptia, in Evaniidte, and some of the genera of AphidiinsB, in Braconida?, 

 theanterior wings are without closed marginal, submarginal ordiscoidal cells; but 

 in the former the abdomen is inserted on the disk of the metathonix, and in the 

 latter the stigma is lanceolate or triangular and well develoi)ed, tlie posterior 

 wings not lohed at base, the median and sometimes the subraedian cell is closed, 

 and the abdominal segments are loosely articulated and capable of being bent 

 beneath the thorax. In some genera of Cynipidse the anterior wings are also 



