156 MISCELLANEOUS STUDIES 



10. Antennal tubercles well formed, strongly rounded on the inner side. 



Typo Aphis cerasi Fabr. Myzoides n.gn. 



Antennal tubercles small or lacking, never drawn out distinctly on inner 



side 11 



11. Body with small tubercles on the middle of the seventh and eighth abdominal 



segments, and often also on the head and prothorax Dentatus n.gn. 



Type Aphis sorbi Kalt. 



Body without tubercles on the middle of the seventh and eighth abdominal 



segments 12 



12. Cubitus of fore wing only once-branched Toxoptera Koch 



Type Toxoptera graminum (Bond.). 



Cubitus of fore wing always twice-branched. Body often with lateral tuber- 



cles 13 



13. Cornicles short, always distinctly conical. Cauda very short, broaa with 



rounded- tip, usually approximately the length of the cornicles, or entirely 

 lacking. Lateral tubercles lacking or only indistinctly formed on the an- 

 terior abdominal segments 15 



Cornicles long, almost cylindrical. Cauda sickle- or club-shaped, usually dis- 



tinctly shorter than cornicles 14 



14. Body long without lateral tubercles. Front often with a very distinct tubercle 



in the middle Myzaphls n.gn. 



Type Aphis rosarum Walker. 



Body more rounded, with lateral tubercles. Front usually flat, never with a 



distinct tubercle Aphis Linn. 



Type Aphis rumicis Linn. 



15. Cauda distinctly separated, almost as long as broad Brachycaudus n.gn. 



Type Aphis myosotidis Koch. 



(Aphis cardui Linn, belongs in this genus.) 



Cauda lacking or scarcely separated, much shorter than broad ....Acaudus n.gn. 



Type Aphis lychnidis Linn. 



16. Cornicles distinctly longer than broad. Cauda usually not conical 17 



Cornicles extremely short, scarcely projecting, cylindrical, usually nearly as 



long as broad. Cauda always conical with broad base 19 



17. Cornicles only a little longer than broad, distinctly conical. Cauda sickle- or 



club-shaped Longicaudis n.gn. 



Type Hyalopterus trirhodus (Walker). 



Cornicles cylindrical, at least twice as long as broad 18 



18. Body with lateral tubercles on first and seventh abdominal segments. Cauda 



small, club-shaped Hyalopterus Koch 



Type Aphis pruni Fabr. 



Body without lateral tubercles on first and seventh abdominal segments. Cauda 



conical Serniaphis n.gn. 



Type Aphis carotae Koch. 



19. Body long, without lateral tubercles. Antennae short, at the most about half 



the length of the body Brachycolus Buckton 



Type Brachycolus stellariae (Hardy). 



Body oval with lateral tubercles on prothorax, first and seventh abdominal 



segments. Antennae at least about three-fourths as long as the body. 

 Type Aphis thalittri Koch. Brachysiphum n.gn. 



Group DREPANOSIPHINA 

 Genus Drepanosiphum Koch. Type Drepanosiphum platanoides Schrank. 



