GENEKIC CLASSIFICATION OF APHIDIDAE. 83 



generations often developed. Cornicles often reduced to mere ringlike openings or 

 entirely absent. Sexual forms small and apterous but with fully developed beaks. 

 Oviparous female laying several eggs. 



Key to the Tribes of the Hormaphidinae. 



1. Aleyrodiform generations developed 2. 



Aleyrodiform generations not developed Oregmini. 



2. Cornicles absent; insects usually gall formers - . .Hormaphidini. 



Cornicles usually present; insects usually not gall formers Cerataphidini. 



Tribe HORMAPHIDINI. 



Members of this tribe are distinguished easily from those of other 

 tribes in that the cornicles are absent and aleyrodiform generations 

 are developed. These remain more or less quiescent upon the 

 foliage. Some different forms of the species are often gall pro- 

 ducers. All secrete wax from special pores. Considerable variation 

 is met with in the development of the aleyrodiform generations. 

 Sensoria of the alate forms are usually narrow and annular. 



Only two genera are so far recorded. 



Key to the Genera of the Hormaphidini. 



Antennae of tbe alate forms composed of three segments, bind wings with 

 only tbe media present Hormaphis . 



Antennae of the alate forms composed of five segments, hind wings with both 

 media and cubitus present Hamamelistes . 



Genus HAMAMELISTES Shimer. 



Plate XIV, T-X. 



1867. Hamamelistes Shimer, Trans. Am. Ent. Soc, v. 1, p. 284. 

 1896. Tetraphis Horvath, Wien. Ent. Zeit., v. 15, p. 6. 



Shimer included two species in this genus, spinosus Shimer and 

 cornu Shimer. The latter species, as suspected by him, is a syno- 

 nym of Jiamamelidis Fitch. This species has been made the type 

 of Hormaphis. 



Characters.— Cornicles absent. Stem mother with four-segmented antennae. Aley- 

 rodiform generations developed. Alate form with five-segmented antennae which 

 are armed with numerous annular sensoria. Wing's held flat in repose; fore wings 

 with the media simple; hind wings with both media and cubitus usually present; cauda 

 knobbed, anal plate bilobed; wax -secreting areas abundantly present in the 

 apterous forms. Sexes small and apterous but with beaks developed, oviparous 

 female laying several eggs. 



Forms living in galls upon the leaves or scale-like on the leaves or twigs. 



Type (one unquestioned species), Hamamelistes spinosus Shimer. 



