12 BULLETIN 45, UNITED .STATES NATIONAL MUSEUM. 



thorns. By sonic autliorities it is cousidered a scleritc of tlie meta- 

 thorax. ri«i-. t</ is the tejiula or wing scale of front winy-. The nieso. 

 pleuron (Fig. inp) is coniix^scd of episternnni and ei)inieron. The uieso- 

 steruum is undivided and is ficqnently not separated from tlie ])leural 

 selerites. 



The metathorax, or third division of tlie thorax, snpixirts the hind 

 wings, hind h>gs, and the al)(h)nien, and it also is (piite variable in 

 length, shape, and seulptnre. The sides (Fig. »ifp) are termed the 

 metapleura, and the sclerite (Fig. fip) extending obli(piely forward 

 from the insertion of the hind legs to the base of the hiud wing and 

 behind the niesoplenron is the metepistermun ; the upper surface (Fig. 

 mn) is the metaiiotum. Fig. sp represents the position of the sjiiracles, 

 while //jM shows the insertion of the hind wings. 



Tlie other normal selerites are not difterentiated. 



TlIK WINOS. 



In shape and neuration, the wings exhibit the greatest diversity, and 

 are of primary importance in classification. As a rule, the hiud wings 

 are veinless or the neuration is meager (PI. i. Fig. o), the highest de- 

 veloped having but a single basal cell. They are rather broad and 

 with a distinct lobe in the Bethylinai, Emboiemiiue, and the Dryinina?; 

 broad in the Proctotryina?, but without a distinct lobe; while in the 

 other groups they are much narrowed toward base, and not esijccially 

 widened toward apex, the apex being sometimes acute. The front 

 wings are entirely veinless in only a single tribe, the Platygasterini, 

 although another tribe, the Inostemmini, in the same subfamily, and a 

 few genera in another subfamily, tlie Scelionime, are almost veinless, 

 having only a submarginal vein terminating in a small knob or stigma. 



The neuration of the anterior wings reaches its fullest development 

 in the Bethylin.e, Enibolemin<i3, Dryiniine, and Ileloriine, although even 

 in these groups there are genera with almost veinless wings {Cephalono- 

 mia, etc.). 



The neuration of the first three of these groups mentioned more 

 closely resembles tliat of the Chrysididje and Scoliidte; the llelorina? 

 and some genera in other groups that of the Braconidie; while some 

 genera in the Scelionin;e closely approach that of the Chalcididiv. 



The great variation in the shape of the wings and the peculiarities 

 of venation are fully brought out in the plates; but as the neuration, in 

 connection with other characters, is of primary importance in a sys- 

 tematic study of the family, it is imi)ortant that the horismology of 

 the wings be fully understood. 



In Figs. 4 and 5, on LM. i, by the use of the front wing of Pristocera 

 atra King, and the hind wing of a Itelytid, as being the most special- 

 ized in tlie group, and, with the explanation given below, the technical 

 terms may be easily acquired. 



