•14 BULLETIN 826, U. S. DEPARTMENT OF AGRICULTURE. 



The genus Myzoaphis was erected by Van der Goot with Aphis 

 rosarum Kalt. and Aphis abietina Walker. These two species show 

 practically no antennal tubercles and are very little different from 

 a typical Aphis, excepting in the clothing of the antennae and body. 

 The cauda as figured by Van der Goot is quite conical, but the 

 writer's specimens are somewhat different from this and specimens 

 of abietinus do not show a cauda exactly like his figure. In fact, 

 they appear more like an Aphis. This genus, therefore, should not 

 be separated or it will necessitate 'the separation of very many 

 other forms under new names. 



Characters. — Head without prominent antennal tubercles. Antennse of six seg- 

 ments and armed with subcircular sensoria. Fore wings with the media twice branched ; 

 hind wings with both media and cubitus present. Cornicles cylindrical or slightly 

 tapering. Cauda usually not as long as the cornicles, subcorneal, rather elongate, 

 constricted about the middle. Anal plate rounded. Males usually winged, oviparous 

 females apterous. 



Type (by suspension of rules), Aphis sambuci L. 



Genus ASPIDAPHIS Gillette. 

 Plate VI, Lr-O. 

 1917. AspidapMs Gillette, Can. Ent., v. 49, p. 196. 



The genus Aspidaphis appears to be related both to Cavariella 

 and to Vesiculaphis. It has the short, blocky form of Vesiculaphis 

 and also the peculiar integument. On the other hand, certain species 

 with a similar integument are met with in Cavariella. The develop- 

 ment of the dorsal abdominal tubercle is here very pronounced and 

 the cornicles have taken on a peculiar shape. 



Characters. — Head without prominent antennal tubercles; antennse short, of five 

 segments, armed with subcircular sensoria. Wing venation normal. Cornicles very 

 small, somewhat swollen near the distal extremity and with the opening in the side of 

 the cornicle, not at the tip. Abdomen with a dorsal caudal tubercle developed into 

 a large conical process extending beyond and fully covering the cauda in the apterous 

 form. Body elongate. 



Type (monotypical), Aspidaphis polygonii Gill. 



Genus ASIPHONAPHIS Wilson & Davis. 



1919. A siphoTiaphis Wilson & Davis, Ent. News, v. 30, p. 39. 



Characters. — Head without prominent antennal tubercles. Antennae of six segments 



armed with subcircular sensoria. Fore wings with the media twice branched; hind 



wings with both media and cubitus present. Cornicles absent entirely. Abdomen 



with large lateral tubercles. Cauda somewhat conical or Aphis-like. Anal plate 



rounded. ■ _ . 



Type (monotypical), Asiphonaphis pruni Wilson & Davis. 



Genus ATARSOS Gillette. 

 Plate VI, P-S. 

 1911. Atarsos Gillette, Ent. News, v. 22, p. 440. 

 Characters. — Head without prominent antennal tubercles. Antennae of six segments 

 armed with subcircular, somewhat tuberculate sensoria; fore wings with the media 

 twice branched, hind wings with both media and cubitus present. Cornicles rather 



