TWO NEW GENERA AND SPECIES OF APHIDIDAE. 



By John J. Davis, 



OFFICK OF THE STATE ENTOMOLOGIST, URBANA, ILLINOIS. 



In his "Catalogue des Aphides de Belgique,"* Dr. H. 

 Schouteden remarks that he has examined specimens of Drepan- 

 osiphum acerifolii Thomas, and concludes "qu'il, s'agit d'un 

 Aphide bien different de nos Drepanosiphiim et qui constituera le 

 type d'un genre nouveau ; la structure des cornicles n'est nullement 

 celle du genre qui nous occupe." For some time I have consid- 

 ered the species acerifolii as probably belonging to an unde- 

 scribed genus. At the suggestion of Mr. H. F. Wilson, of the 

 U.S. Department of Agriculture, who was also of the opinion that 

 it l)elonged to a new genus, I ha\-e made a careful study of the 

 descriptions of Drepanosiphiim and its respective species, and 

 have also had the opportunity of comparing acerifolii with D. 

 braggii Gil. and D. plaianoides Schrank through the courtesies of 

 Professor C. P. Gillette and Mr. Wilson respecti\-eh'. 



I herewith erect the genus Phymatosiphum to hold a new 

 species. P. monelli and that one previously known as Drepan- 

 osiphiim acerifolii Thomas. 



Phymatosiphum genus novum. 



This genus is at once distinguished from Drepanosiphiim, to 

 which it is closely related, b>' the cornicles. In Drepanosiphiim 

 the\' are long and curved, while in Phymatosiphum they are 

 shorter and decidedly swollen at the base. The stigma of the 

 former genus, according to the various descriptions and from 

 examinations by the writer of D. braggii and D. plaianoides, is 

 long and narrow, while in the latter it is shorter and broader, and 



^ji 



has a more distinct whitish central stigmal area. 



t>' 



Description; Antennae on frontal tubercles; longer than the body; 

 the filament of VI long and threadlike, it being longer than any of the 

 other segments; a single row of large, circular sensoria on the basal 

 half or two-thirds of segment III. Eyes bright red. Beak rather 

 short. Wings long and narrow, marginal cell elongated towards the 

 ape.x, small dusky patches at the tips of the veins and sometimes a 

 slight dusky shading along the veins, the stigma brownish excepting a 

 clear central area (PI. XXVII, Fig. 1). Fore femur with a prominent 



*Memoires de la Societe entomologifiue de Belgique, tome XII, p. 237, 1900. 



196 



