No. 34-] HEMIPTERA OF CONNECTICUT I APHIDIDAE. 283 



Fore wing with the media twice branched ; hind wing with both 

 media and cubitus present. Cauda distinctly knobbed ; anal plate 

 entire, sometimes slightly indented. Sexual forms not differing 

 markedly from the viviparous ones. Males winged, intermediate 

 and apterous often in the same species. 



Forms living usually upon foliage. No small dimorphic forms 

 developed. 



Key to Species.* 



Vertex and crown covered with reticulate areas ; segment iv of 

 antennae with 4-6 sensoria; dorsum of apterous form reticulate 



nigrae 



Vertex and crown without reticulations but these replaced by- 

 granulations ; segment iv of antennae with usually not more than 

 2 sensoria ; apterous form granulate viminalis 



C. viminalis Monell. C. stevensis Sanborn. 



Bull. U. S. Geol. Geog. Surv. Terr., v, 31, 1879. 



On Populus grandidentata. 



New Haven, 29 June, 1914 (M. P. Z.). 

 C. nigrae Oestlund. C. cordata Williams. 



Aphid. Minn., 49, 1886. 



On willow. 



Yalesville, 15 July, 1909 (W. E. B.). 



Neothomasia Baker, 

 (n. n. for Thomasia Wilson.) 



Cornicles present, truncate in form. Antennae of six segments 

 armed with subcircular sensoria. Fore wing with the media twice 

 branched ; hind wing with both media and cubitus present. Cauda 

 and anal plate both rounded. 



Forms living in colonies upon the leaves or bark of trees ; no 

 small dimorphic forms developed. 

 N. populicola (Thomas). Chaitophorus populicola Thomas. 



111. St. Lab. Nat. Hist, Bull. 2, 10, 1877. 



The only species recorded from New England. 



On Populus. 



New Haven, 22 July, 1909 (A. I. B.). 



Periphyllus Van der Hoven. 



Cornicles truncate, often sculptured. Antennae of six segments 

 (not including the dimorphs) armed with oval sensoria. Fore 

 wing with the media twice branched ; hind wing with both media 

 and cubitus present. Cauda and anal plate rounded. 



* Chaitophorus delicata Patch, known only from the apterous forms, is 

 not included in the key. 



