August, '17] BAICER: EASTERN APHIDS, PART II 423 



synonjan. Yet when we come to examine the anal plate of walshi we 

 find that manj' specimens show a typical IM^^zocallis anal plate. The 

 prothorax in tilioe is somewhat different from that of most species of 

 Myzocallis and this is also approached b}' hellus and walshi. Yet 

 other species vary toward it. Here then we have the choice of placing 

 tili(£ and hellus in Eucallipterus and most specimens of walshi in 

 Myzocallis or of transferring tilioe to Myzocallis wherein hellus was 

 described and the other species since placed. The latter method has 

 been adopted by the writer in that it would seem to simplify matters. 

 The species needs no descriptive remarks since an excellent description 

 has been given by Davis. (1909, p. 33.) 



The following key will distinguish the American species of Myzocallis. 



Key to American Species of Myzocallis 

 (Alate viviparous females) 



1. Dorsum of abdomen with finger-like tubercles 2 



Dorsum of abdomen without such tubercles 7 



2. Unguis of segment VI about equal in length to the base 3 



Unguis of VI twice as long as base pundatellus (Fitch) 



3. Cornicles long (nearlj- 0.112 mm.) abdomen greenish 4 



Cornicles short (0.064 mm. or less) 5 



4. Segment VI less than width of head across eyes calif ornicus Baker 



Segment VI much longer than width of head across eyes pasanioE Davidson 



5. Segment III of antenna; shorter than the width of head across eyes, abdominal 



tubercles setose and dark brown; cornicles about 0.06 mm. 



fumipennellus (Fitch) 

 Segment III longer than width of head across eyes 6 



6. Cornicles about 0.06 mm. long and black quercus (Kalt.) 



Cornicles about 0.032 mm. long and not black ulmifolii (Mon.) 



7. Entire margin of wing with a rather broad dark browm band 8 



Margin of wing without such dark brown band 10 



8. Unguis of segment VI more than twice as long as base, hind tibiae yellowish 



walshi (Alon.) 

 Unguis of segment VI less than twice as long as base 9 



9. Antennte distinctly annulated with dark brown ; segment III with 10 to 12 oval 



sensoria, tips of the wing veins marked with brown tilioe (L.) 



Antenn£e uniform yellowish or dusky; segment III with about four circular 

 sensoria; tips of wing veins not marked -ndth brown bellus Walsh 



10. Unguis of segment VI about equal to or less than the length of the base 11 



Unguis of segment VI considerably longer than the base 14 



11. Abdomen with a number of dark spots 12 



Abdomen uniform green or j'ellowish green 13 



12. Antenna? annulated, segment III with 4 to S sensoria close to base of segment 



arundicolens (Clark) 

 Antennae yellowish or dusky; segment III with a row of 10 or 12 sensoria 

 covering about three-quarters of the segment trifolii (Mon.) 



13. Anal vein and base of cubitus and of media much heavier than the other 



veins of the wing alnifolice (Fitch) 



Venation nearly uniform rohinice (GiU.) 



