THE CANADIAN ENTOMOLOGIST. 69 



SOME PLANT -LICE AFFECTING PEAS, CLOVER AND 



LETTUCE. 



BY E. DWIGHT SANDERSON, NEWARK, DEL. 

 ( Continued from page jg. ) 



Lettuce Aphids. 

 Nectarophora lactucce, Walk. 



(PI. III., 8.) Several writers have listed S. lactucce, Kalt. as an 

 American species. That of Thomas is noted below. Dr. j. B. Smith 

 gives the species in his Insects of New Jersey. Whether the species 

 occurs in this country or not is open to question. It should be noted 

 here that Kaltenbach's Aphis lactucce is a Rhopalosiphum. Buckton 

 gives both Siphonophora lactucce, Kalt. and Rh. lactucce, Kalt., though 

 Kaltenbach described but one species. Walker (Ann. and Mag. Nat. 

 Hist., Ser. 2, p. 49, 1849) in his description of the species confused it 

 with Rh. lactucce, Kalt., as Passerini has pointed out. Walker described 

 it as Aphis lactucce, Linn, and as a synonym of A. lactucce, Kalt. 

 though Kaltenbach had already shown A. lactucce, Linn, to have been 

 invalid, and that his species was entirely distinct. Walker also gives 

 A. ribis-nigri, Mosley (Gard. Chron. I., 684) as a synonym. Mosley's 

 description is hardly recognizable, but evidently is the same as some of 

 the varieties described by Walker, both undoubtedly referring to Rho- 

 palosiphum ribis, Linn., and Myzus ribis. Unfortunately, Walker de- 

 scribes only the coloration of his species. Part of his species is evidently, 

 however, N. lactucce. Passerini's description is too brief to be recog- 

 nizable, but probably refers to the same species, as Buckton thought. 

 Why Buckton described the species as S. lactucce, Kalt., is not clear. 

 Buckton follows Walker in giving Ribes nigrum and grossularia as 

 food-plants, and remarks that Walker states that the cornicles are 

 enlarged at the middle, but does not otherwise seem to confuse the 

 species with others as did Walker. Mr. Buckton has kindly loaned me 

 specimens which correspond very closely with his description. The 

 slide is labelled, "(18) A. R. Siphonophora lactucce," and " S. lactucce, 

 Walk." They are as follows : 



Winged Viviparous Female. 



Length, 2.32 mm.; width, 0.82 mm.; antennae, 3.10 mm.; III., 0.73 

 mm., IV., 0.50 mm., V, 0.41 mm., VI., 0.12 mm., VII., 1.11 mm.; 

 Tibia, I., 1.35 mm., II., 1.45 mm., III., 1.85 mm.; Cauda, 0.19 mm.; 



