THE CANADIAN ENTOMOLOGIST 91 



Aphis salicola, Cowen, Hemip. of Colo., Bui. 31, p. 121, 1895. 



Morgan, Jour. Exp.Zool., vol. VII, p. 301, 1909. 

 Aphis salicicola, Davis, Jour. Ec. Ent., vol. 3, p. 490, 1910. 



Williams, Aphididae of Neb., Univ. Studies, vol. 10, No. 2, 



p. 55, 1910. 

 Aphis saliceti, Theobald, Rep. on Ec. Ent. for 1912, p. 84 {thed- 



haldi) . 

 Aphis salicicola, Davidson, Jour. Ec. Ent., vol. 5, p. 408, 1912. 



Patch, Bui. 213, Me. Exp. Sta., p. 81, 1913. 

 Siphocoryne saliceti,'Bornev, Blattlausstudien, in Abhand, Naturwiss. 



Ver. Bremen, XXIII, pt. I, p. 164, 1914. 

 Aphis saliceti, Van der Goot, Beitrage zur Kenntnis der HoUand- 



ischen Blattlause, p. 225, 1915. 



The salicicola of Thomas is undoubtedly a synonym of sali- 

 ceti Kaltenbach, and the cases where the specific name is given as 

 "salicola'' are errors in spelling, Cowen being the first offender, 

 and others following. 



This species is of special interest because of the cytological 

 work done upon it by Dr. N. M. Stevens and Dr. T. H. Morgan. 

 We happen to know this is the species that was worked with as 

 specimens were submitted to us by Dr. Morgan for identification. 

 It differs from the others mentioned in this paper in its habit of 

 remaining upon the willows throughout the year, and seems not 

 to have an alternate summer host. It is also peculiar among the 

 aphides, that deposit over-winter eggs, in that the sexual forms 

 appear very early in the summer. We have taken the males and 

 oviparous females at Fort Collins as early as June 20, and the eggs 

 before the end of June. We know no other species approximat- 

 ing it in this respect. Our records for the capture of the sexual 

 forms are as follows: 



Woods Hole, Mass., June 29, 1909, L. C. Bragg. 



Geneva, N. Y., June 30, 1909, C. P. Gillette. 



Fort Collins,' Colo., July 14, 1910, L. C. Bragg. 

 " June 17, 1912, L. C. Bragg. 

 " June 20, 1912, L. C. Bragg. 



Lansing, Mich., July 12, 1912, C. P. Gillette. 



Fort Collins, Colo., July 30, 1912, L. C. Bragg. 



Manitou, Colo., June 14, 1917, L. C. Bragg. 



