56 MAINE AGRICULTURAL EXPFRIIVTENT STATION. I914. 



and a quadrate patch on the abd'omen become black. This 

 quadrate black patch is 3-barred at the sides and covers 3 seg- 

 ments, the caudal edge being about on a line with the cornicles. 

 In some collections this black dorsal decoration extends across 

 the abdomen in transverse bars instead of a solid patch. 



Structural details of the antennae and wing are shown in the 

 figures. The venation is erratic and no single wing can be 

 chosen as surely "typical". 



In life it is distinguished from the species next discussed by 

 being characteristically lemon yellow and being more flatly 

 appressed to the leaf. The two species are frequently inter- 

 mingled upon the same leaf and are very likely both confused 

 under the name ribis. I do not know which species has best 

 claim to the name ribis but have been guided in my usage by 

 specimens from the collections of other entomologists. 

 • In balsam mounts the two species are most readily separated 

 upon antennal characters. In ribis the terminal sensorium. of V 

 and the sensorium at base of spur on VI approximate the articu- 

 lation between V and VI much more closely than is the case 

 with dispar. Ill is more slender in ribis and the sensoria are 

 proportionately larger. This portion of the antennge of these 

 two species is given (Figs. 12 and 13) drawn to the same scale 

 and shows the distinctions here described. (30-13). 



Fig. 12. Myziis ribis (30-13)- Section of antenna of alate female for 

 comparison with Fig. 13 which is drawn to the same scale. 



Fig. 13. Myzus dispar (29-13). Section of antenna of alate female 

 for comparison with Fig. 12 which is drawn to the same scale. 



Myzus dispar n. sp. 



Figs. 13, 16, 17, 18, 37. 



Collections of Myzus from gooseberry and currant in Maine 

 show two closely allied species. The differences though rather 



