DEL GUERCIO, NEW GENERA OF APHIDS 75 



AA. Posterior wings with the two obhque veins united at the Ijase. causing the 

 subcostal to appear trifid at the point of division. 



Genus Trifidapliis Del Guercio. 



( Sp. tip. Pemphigus mdicicola Essig.) 



Trifidapliis radicicola (Essig) was collected for the first time at Santa 



Paula in California in November, 1908, on the roots of Amarantus retroflexus, 



on which we have also found Tctrancitra phaseoli (Pass.). T. radicicola was 



collected on the roots of Solanum douglasii near Claremont, California. 



