16 
and incloses, with the terminal dorsal are (pygidium), the claspers and 
sexual organs. To use these latter in description requires dissection, 
and they have not, therefore, been referred to. 
In the female the sheath of the ovi- 
positor has been referred to through- 
out the descriptions, and the more 
prominent variations consist in its 
width and in the character of the 
upper and lower margin and of the 
apex. The hairy vestiture, particularly 
that of the extreme apex and the lower 
margin, also presents good specific char- 
acters. The cerci are either very short, 
robust, or spindle-shaped, or are very 
elongate and slender. 
In the males the apex of the seventh 
dorsal segment and the terminal ven- 
tral segment are useful, particularly in 
Via. 5.—Abdomen of Pachynematus erichsonii, : : 
lateral and ventral. views: Segments num. SCeric Separation, and also presentspe- 
hered 1 to 9; a, spicule plate; b, basal por- cific features, particularly in the termi- 
cea portion of sheath, og chosth proper. 2A prolongation from the center of the 
enlarged (original). seventh dorsal segment, which projec. 
tion, following Konow, is referred to in the descriptions as the proci- 
dentia. Thenarrow projecting tip of this segment is usually thickened 
and prominent, and varies in its width relative to its length and in the 
character of the constriction, or 
otherwise, of its base. — 
The subject of the venation of @~ «<== 
Tenthredinidie has been fully £24 SS 
discussed elsewhere and need @-==== 
not be referred to atlength here.! ? j 
The normal venation of the Ne-  ; 
matines is indicated in the ac-  ‘ 
companying figure (fig. 6). Of % 
importance in specific character- Fie. 6.—NEvuRAtTION OF NEMATINES: Longitu dinal 
B : ; veins.—a, costal; b, subcostal; c, median; d, anal; e, 
ization are the intercostal cross accessory; f, axillary; g, inferior; h, radial; i, eubi- 
vein in its relation to the basal tal; j, subdiscal. Cross veins.—k, transverse costal; 
vein, and its angle with the 2 jer, 9 usure eta) see 
costa; the second reeurrent vein, second transverse medians. Cells.—1, costal; 2, sub- 
as to whether interstitial With ee ee ae ci tindaienies i 
the second transverse cubital or 16, firstand second posteriors. (In the hind wing cells 8 
received beyond or within the 418 are usually termed the discal cells). (Original.) 
latter; and in the posterior wings, the relation of the outer veins of the 
discal cells. The shape of the cells of the anterior wings is of compara- 
tively little importance, with the exception of the third cubital, which 
‘Proc. Ent, Soc, Wash., U1, pp. 78-82, 
