June, '11] GILLETTE: APHID ID -E 321 



scribed and figured this species as pastinacce has had much to do to 

 cause the confusion of later writers. Koch's caprece seems to be 

 neither this species nor pastinacce. Buckton ^ recognized the prom- 

 inent distinctive characters of the two species, as did Passerine. Mr. 

 J. T. Monein obtained his salicis from willow and described the 

 winged form without noticing the small supra-caudal tubercle. In 

 a recent letter Mr. Monell has told me that he now considers his 

 salicis synonymous with caprece Kalt. Doctor Weed ^ later found the 

 sexuales of this species on willow in Ohio and described them as 

 Siphocorince salicis Monell. Mr. J. J. Davis has called my attention 

 to the fact that Doctor Oestlund ^ seems to have described this louse 

 as archangelicce which seems to me to be the case, I have not come 

 upon any description of pastinaccB since Buckton's, already men- 

 tioned, except that of xylostei Schr., which is probably a synonym 

 of this species. The striking character in caprece, which in the material 

 that I have studied is constant in all forms, larvae, alate and apterous 

 viviparse, sexuales, and pupse, is the supra-caudal tubercle or spine 

 which, in the apterous form, is as long or longer than the cauda, but 

 which is a tubercle only in the alate forms (See figures.). 



All the specimens of these two forms that I have seen, separate 

 readily into two very distinct species without intergrading, and without 

 a mingling of the two forms in the same lot as follows: 



Joints 4, 5, 6, and antennal spur sub-equal, the spur usually distinctly the longest, 

 cornicles fully % as long as 3d joint of the antenna, a small tubercle on the alate 

 form and a large one on the apterous individuals always present caprece. 



Joint 6 of the antenna distinctly shorter than 5, the 4th still shorter and its spur 

 nearly as long as joints 4, 5 and 6 combined, cornicles seldom much exceeding J^ the 

 .3d joint of the antenna in length, and supra-caudal tubercle or spine entirely absent 

 pastinacce. 



Kaltenbach called attention to the interesting habits of caprece 

 in that it lived upon two very different groups of plants, the willows 

 (Salix species) and several species of the Umbelliferae. Later writers 

 have added to the number of food plants but, so far as I have learnedj 

 they have all been willows or members of the parsley family. 



The food plants given for caprece by the writers mentioned, and by 

 Fabricius and Schrank are as follows: 

 Fabricius. — Salix caprece. 

 Schrank. — Willow. 



Kaltenbach. — Salix amygdalina, babylonica, caprece, and alba, Her- 

 acleum siphonchjlium, Angelica sylvestris, Aegopodium podograria, 

 Choerophyllum iemulum, Pastinacea saliva and Conium macula- 

 turn. 



'Monograph of British Aphids, II, pp. 25, 27. 

 «Bull. 5, U. S. Geol. Survey, 1879, p. 26. 

 ^Trans. Amer. Ent. Soc, 20, 1893, p. 297. 

 'Aphididae of Minn., 1887, p. 70. 

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