POSTERIOR WIXGS. 13 



one at the base and a larger one at the apex. This is 

 a contracted lanceolate cellule, and is possessed by 

 Zarcea, Abia, Amasis, Hylotoma, Monoctenus, Cladi*, 

 Camponiscus, Hemichroa, Hoplocampa, Macrophya (in 

 part), Syncerema (PI. X, fig. 12 e). 



III. The accessory nervure touches slightly the 

 anal in the middle, thus forming two cellules of 

 nearly equal length. To this form the term subcon- 

 tracted has been applied, and we meet with it in 

 Pachyprotasis, Macrophya in part (PL X, fig. 12 b). 



IV. The nervure does not touch the anal nervure at 

 all ; this form may be either open or closed. It may 

 be closed by 



(a) An oblique cross nervure placed beyond the 

 middle of the cellule as in Dolerus, Emphytus, Phyllo- 

 toma, Eriocampa, Athalia, Taxonus, Poecilosoma, 

 Tarpa, Lyda, and Pinicola (PL X, fig. 12 a), or by 



(b) A straight cross nervure in the centre of the 

 cellule as in Tenthredo, Tenthredopsis, Allantus, Cimbex, 

 Trichiosoma, Clavellaria, Lophyrus (PI. X, fig. 12 c). 



(c) Without any cross nervure, as in Selandria, 

 Strongylog aster in part, and Aneugmenus (PI. X, fig. 

 12). 



The posterior wings have never a stigma, but may 

 have an appendicular cellule (Hylotoma). They are 

 divided into cellules like the anterior, but they are 

 fewer in number and in importance. 



The most important feature in classification is the 

 presence or absence of the transverse cubital (PI. X, 

 fig. 1 g, lower wing) and recurrent nervures (fig./). If 

 absent the inner cubital cellule (fig. 5) becomes con- 

 fluent with the outer (fig. 6), and the discoidal (fig. 8) 

 with the posterior (fig. 9). Generally both nervures 

 are present, but with Monophadnus, Harpiphorus, 

 Poecilosoma, the transverse cubital is absent, and the 

 recurrent present ; while with Emphytus, Fenusa, Phyl- 

 lotoma, Blennocampa, Taxonus, neither is present. 

 According as these nervures are absent or present, the 

 species are said to have no middle (or discoidal) 



