THE GROUP OF BETUUE. 137 



nigricornis, Lep., Mon., 63, 186; Ste., Mon., vii, 37, 42, with the 

 description of which it agrees tolerably well, but is still too indefinite 

 to warrant the sinking of the later names. 



XY. THE GROUP OF 



Body black, the abdomen, generally part of mesopleura, 

 and always the metapleura, orange-yellow. Legs pale 

 luteous, the apex of hinder tibice and tarsi blade. 

 Abdomen rarely with a row of narrow, blade spots on 

 dorsum. Clypeus truncated. Wings hyaline, costa and 

 stigma fuscous, or black: the third cubital cellule not 

 much longer than broad. Antennce blade, brownish 

 beneath. 



The only group of Nemati with which N. betulce and 

 its allies can be confounded is that of N. salicis which 

 has pretty much the same coloration, including the 

 black stigma, but differs in the species being larger, 

 in their having the pleurge more largely yellow, the 

 antennae not so decidedly yellow beneath when it is not 

 entirely black, and especially in the incised clypeus. 



Synopsis of Species. 



1 (6) Mesopleurse with a large orange-yellow mark ; sides of meta- 



notum black ; abdomen black at base, or with a black line 

 on back. 



2 (5) Clypeus black at the base. 



3 (4) Posterior tarsi and apex of tibiae black ; apex of clypeus white ; 



abdomen with a black band down the back. Conjugatus. 



4 (3) Posterior tarsi and apex of tibiae testaceous ; clypeus black ; 



abdomen black only at base. V. flavum. 



5 (2) Face entirely white ; abdomen only black at extreme base ; 



spurs not reaching to middle of metatarsus. Subbifidus. 



6 (1) Mesothorax entirely black ; sides of metanotum luteous. 



Betula. 



