16 
and incloses, with the terminal dorsal arc (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, 
a, 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 
generic separation, and also present spe- 
bered 1 to 9; «. Bpicuie plate; b. basal por- ciiic features, particularly in the ternii 
^^SSSSTiSSSS^ " :l1 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. The narrow 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 
Tenthredinidae has been fully 
discussed elsewhere and need 
not be referred to at length here. 1 
The normal venation of the Ne- 
matines is indicated in the ac- 
companying' figure (fig. 0). Of 
importance in specific character- Fl °- o.— neuration of nematines: Longitudinal 
veins. — a, costal; b, subcostal; c, median; d, anal ; e, 
Fig. 5. — Abdomen <>t PachynemaAMaeriehaonii 
Lateral and ventral views: Segments nnm 
ization are the intercostal cross 
vein in its relation to the basal 
vein, and its angle with the 
costa; the second recurrent vein, 
as to Avhether interstitial with 
the second transverse cubital or 
received beyond or within the 
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 
accessory;/, axillary; g, inferior; h, radial; i, cubi- 
tal;,;', subdisra!. (Jross veins.— k, transverse costal; 
m. n. o, first to third transverse cubitals j j>, basal; g 
and r, first and second recurrcnts; .s- and t, lirst and 
second transverse medians. Cells. — 1, costal; 2, sub- 
costal; 3, median; 4, lam -relate : 5, anal; G, radial; 8-11, 
lirst to fourth cubitals ; 12-14, first to third diseals; 15, 
16, first and second posteriors. (In tbe bind wing cells 8 
and 13 are usually termed tbe discal cells). (Original.) 
1 Proc. Ent. Soc. Wash., ill, pp. 78-82. 
