August, '17] BAKER: EASTERN APHIDS, PART II 431 



Vertex and crown without reticulations but these replaced by granulations 

 (especially on apterous form) Segment IV with to 2 sensoria . . . .viminalis Mon, 



8. Segment IV with 4 to 6 sensoria nigrm Oest. 



Segment IV with no sensoria salicicola E,ssig 



N. B. ChaitopJiorus agropyronensis Gillette is a species of Sipha 

 Chaitophorus flabeUus Sanborn is a species of Saultusaphis 

 Chaitophorus betula; Buckton of GiUette is a species of Callipternella 

 Chaitophorus artemisios GiUette seems to be the same form described as 



Cryptogsiphum canadensis by Williams. It is not a Chaitophorus. 

 Chaitophorus spinosus Oest., is a synonym of quercicola Mon. 

 Chaitophorus cor data Wms., is a synonym of nigrae Oest. 

 Chaitophorus stevensis Sanborn is a synonym of viminalis Mon. 

 Chaitophorus delicata Patch is known only from the apterous forms and is 



therefore not included in the key 

 Chaitophorus Iridentata Wlsn., the writer has not seen. 



Genus Pterocomma Buckton 



Pterocomma media n. sp. Taken on poplar, Manchester, Conn., Sept. 

 3, 1909, by A. I. Bourne Conn. No. 1-16/126 and on Carolina pop- 

 lar, New Canaan, Conn., Sept. 21, 1909, by A. I. Bourne, Conn. No. 

 1-16/127. 



Alate Viviparous Female: General appearance similar to beulahen,sis Ckll., 

 from which it differs chiefly in the antenna} and cornicles. Antennae as follows. III, 

 0.56 mm.; IV, 0.32 mm.; V, 0.272 mm.; VI (0.16 mm. +0.192 mm.). Segment III 

 is covered with a large number of rather small circular sensoria ; more distal segments 

 without sensoria. Cornicles 0.256 mm. long, shghtly stouter than those of beula- 

 hensis, being about 0.096 mm. in their greater diameter. They are flanged and some- 

 what swollen in the middle. Length of forewing 4.28 mm. Hind tarsus 0.24 mm. 

 long, labium extending to the hind pair of coxae. Length from vertex to tip of cauda 

 about 3 mm. The color characters cannot be obtained from the mounted specimens 

 and no color notes were taken. 



Apterous Viviparous Female: Antennal segments as follows: III, 0.544 mm.; 

 IV, 0.256 mm.; V, 0.24 mm.; VI (0.144 mm. + 0.176 mm.). Segments without 

 sensoria. Cornicles 0.256 mm.; hind tarsi 0.24 mm. Labium extending almost to 

 hind pair of coxae; length from vertex to tip of cauda about 3 mm. 



Described from specimens in balsam mounts. 

 Type in U. S. National Museum. Cat. No. 20346. 



Key to the American Species of Pterocomma 

 (Alate viviparous females) 



1. Cornicles without a distal flange and abruptly constricted at the distal extrem- 



ity flocculosa (Weed) 



Cornicles with a distal flange and not so abruptly constricted at their distal 

 extremities 2 



2. Cornicles about twice as long as their greatest diameter smithios (jNIon.) 



Cornicles much more than twice as long as their greatest diameter 3 



3. Cornicles about equal in length to the hind tarsi 4 



Cornicles much longer than the hind tarsi 6 



4. Cornicles cylindrical, beak long . populea (Kalt.) 



Cornicles somewhat swollen, beak short . . . • 5 



