STATE HORTICULTURAL SOCIETY. 1()3 



The wingless females are larger than the others, though less than 

 one-tenth of an inch in length, slightly powdered and generally more of 

 a yellowish-green than the males ; the eyes, two large spots on the top 

 of the head and one on each side of the neck, black ; the honey-tubes 

 short and dark, as are also the legs. 



The winged individuals measure about one-seventh of an inch to tlie 

 tip of the wings, and half that length to the tip of the abdomen ; dull 

 green or pea-green ; head and throax black above, abdomen more or less 

 varied with black. The honey-tubes, though not long in this species, are 

 distinct ; antennae about two-thirds the length of the body. Winged 

 specimens are met with throughout the season. 



29. Aphis rmnicis, Linn. The Bean Plant-louse. 



This is said to be one of the most injurious species of the entire 

 group, not confining its attacks to a single plant, but spreading its colo- 

 nies over a variety of species, on which account it has received a variety 

 of different specific names, which Mr. Walker has enumerated as follows : 

 A. rumicis, Linn. ; A. cracca', Linn. ; A. atrip/icis, Linn.; A.fabce, Scop. ; 

 A. getiistce, Scop.; A. acetosa, Linn.; A. aparines, Fabr. j A. euonymi, 

 Fabr. ; A.papaveris, Fabr. ; A. hortensis, Fabr. ; A. vicce, Fabr. ; A. cheno- 

 podii, Schrank ; A. ihlaspeos, Schrank ; A. galliscabf-i, Schon. ; A. armaia, 

 Hans. ; A. laburni, Kalt. ; A. dahli(E, Mos.* 



These names indicate the various plants on which it has been ob- 

 served — as, the dock {Rumex), the tufted vitch {Vicia cracca), the garden 

 orache {Atriplex), the bean (^Fabd), the dyer's broom {Genista), the field 

 sorrel {^Rumex acetosa), the bedstraw {Galium aparine), the burning-bush 

 {Euonytnus), the poppy {Papaver), the pig-weed {Chenopodium), the 

 shepherd's purse {Thlaspi), the dahlia {Dahlice). They also show that 

 not only is it not confined to a single species, or a single genus of plants, 

 but feeds alike upon those belonging even to different orders, thus setting 

 at nought what is considered as an inflexible rule in regard to all other 

 species. I think it more than probable the facts presented by this will 

 ultimately lead to a more thorough examination of other species, and 

 show that many which are now considered as distinct species are but 

 varieties. 



It may be asked. How is it known that t.hese various supposed species 

 are but varieties of but one species? By the peculiar marks and charac- 

 teristics which distinguish it from all other species. Yet it is possible 

 that some of these are after all distinct, and that Koch is right in restor- 

 ing them to their position as such. 



Winged females glossy black, one-twelfth of an inch to tip of the 

 abdomen, and one-sixth of an inch to tlie tips of the closed wings; an- 

 tennae shorter than the body, (Dr. Fitch says half the length of the body, 

 but this appears to be the minimum, as it is sometimes nearly as long as. 

 the body,) undistinctly seven-jointed, third longest, sixth shortest of all, 



* Note. — Koch has removed several of these as distinct, and Walker has accepted the change ir» 

 the Supplement to his Catalogue. 



