27 



The scape of the antennae is in O. angustifrons 1 } 

 times, but in O. popiili \\ times as long as the 1st joint 

 of the funiculus, this joint being in the former, as above 

 described, U times as long as the 2nd joint, whereas in 

 O. popiill it is almost as long as the 2nd joint. The sides 

 of the thorax are in O. angustifrons by far not so strongly 

 rounded, and the club of the antennae not so elongate 

 as in O. populi. 



From O. sal'iceti it may at once be distinguished by 

 the six-jointed funiculus. 



The species was found abundantly near Copenhagen 

 (in Lersøen and Damhusmosen) on Salix viminalis, preferably 

 in the months of June and September. 



Type specimen in my collection. 



