54 BULLETIN 826, U. S. DEPARTMENT OF AGRICULTURE. 



2. Cornicles cylindrical at base and extremity; abruptly swollen in middle. . 



Rhopalosiphoninus. 



Cornicles 'with the swelling gradual 3. 



3„ Head with a large central process on vertex. Francoa. 



Head without this 4, 



4. Antenna! tubercles large and diverging 5, 



Antennal tubercles converging; head and basal antennal segments with 



very prominent capitate hairs Capitophorus. 



5. Cornicles much longer than cauda which is somewhat tapering. . Amphorophora. 

 Cornicles about the length of cauda which is usually constricted near its 



base ' Megoura. 



6. Cornicles very small, much smaller than the long, broad cauda. .Hyalopteroides. 

 Cornicles as long as or longer than the cauda 7. 



7. Head with prominent, elongate projections to the antennal tubercles, par- 



ticularly evident in the apterous form Phorodon. 



Head without these 8, 



8. Tubercles strongly converging Myzus. 



Tubercles distinctly diverging 9. 



9. Cornicles thick, about as long as the cauda which is large and somewhat 



constricted near base Macrosiphonella. 



Cornicles very long, rather slender, subcylindric, somewhat tapering 10. 



10. Cauda elongate, constricted near base Macrosiphurn . 



Cauda moderate or elongate, not constricted near base 11 . 



11. First antennal segment and abdominal segments with long fingerlike tuber- 



cles in the apterous form Acanthaphis. 



Without these Iilinoia. 



Genus ACANTHAPHIS Matsumura. 

 Plate VII, R-Ti. 



191S. Acanthaphis Matsumura, Trans. Sapporo Nat. Hist. Soc, v. 7, pt. 1, p. 15. 



The genus Acanthaphis Mats, is somewhat related to Phorodon. 



Characters. — Head with prominent diverging antennal tubercles. Antennae of six 

 segments, first segment with a long fingerlike projection in the apterous form. Corni- 

 cles long, slender, and cylindrical. Cauda elongate, conical. Dorsum of abdomen 

 with long fingerlike tubercles. Body with capitate hairs. 



Type (fixed by Matsumura, 1918), Acanthaphis rubi Mats. 



Genus AMPHOROPHORA Buckton. 



Plate IV, A, B. 



1876. Amphorophora Buckton, British Aphides, v. 1, p. 1ST. 



1886. Macrosiphurn Oestlund, Minn. Geol. Survey Rept. 14, p. 27. 



1900. Macrosiphurn Del Guercio, Nuove Rel. Staz. Firenze, ser. 1, no. 2, p. 159, 



1901. Ncctarosiphon Sehouteden, Ann. Ent. Soc. Belg., v. 45, p. 112. 

 1913. Eunectarosiphon Del Guercio, Rcdia, v. 9, p. 188. 



1913. Rhopalosiphum Van der Goot; Tijd. voor Ent., v. 56, p. 146. 



Buckton erected his genus Amphorophora for his ampuUata which 

 he had secured in the apterous form only. Oestlund gave th,e generic 

 name Macrosiphurn to a species he described as rubicola. In his sec- 

 ond paper Oestlund describes a species under the name ampullata 

 Buckton and sa}^: 1 "The length of the antennas, together with the 

 distinct frontal tubercles, may justify our exception of Ampho- 

 rophora as a good genus." In speaking of his Macrosiphurn 



i Bui. 4, Geol. and Nat. Hist. Surv. Minn., p. 77, 1887. 



