4 
BULLETIN 2^6^ U. S. DEPAKTMEXT OF AGKICULTUEE. 
the interpretations of Cholodkovsky, Mordwilko, and Theobald that 
species heretofore considered as synonomous with j^isi, namely gei 
Koch, nlmariae Schi'., and ononis Koch, are good and distinct species 
and that onohrychis B. de Fonsc. is still a doubtful species. 
Our own results pubhshed herein assure us of the identity of the 
pea aphis {pisi Kalt.) occurring in America and Eirrope. In America 
there seem to be only two names, originating here, which can properly 
be considered synonyms of pisi Kalt., namely destructor Johnson and 
tiifoVii Pergande. 
The synonymy of ^lacrosipliura pisi Kaltenbach, as wenowimder- 
stand it, is as follows: 
MacrosiptLum pisi (Kaltenbacli). 
Aplils pisiijn^2iTT\s. 
ApJ'i.s hithyri'SLosley. 
AiJ''s nnnhrycMs B. de Fonsc? 
Aphis pisi Kaltenbach. 
Siphoiiophorn pisi Knch. 
Siphonophora 'ij/nariae Passerini (nee Schrank). 
Xtctarophora pisi OesTlund. 
Xcctarophora dc-^f ;'•''<■/',/' Tnlmson. 
Macrosiphum pisi S.-hi jut^den. 
Macrosiphu/n tr'jni.i Pergande. 
IDENTITY OF THE SPECIES OCCURRING IN AMERICA. 
Macrosipliurn pisi was first reported in America by Cyi^us Thomas 
in 1878, although this- record has been incorrectl}' discredited by most 
subsequent authors. In 1900, followmg the first noteworthy out- 
break of this pest in the United States, Johnson described the species 
as new, calling it XectaropJiom destructor. The following year San- 
derson reported studies to show that destructor is identical with pisi 
of Europe, basing his conclusions partly by comparison with speci- 
mens labeled p)isi from Buckton. Evidently Buckton was confused 
on this species, since one of the species sent Sanderson was certainly 
not pisiAoY the tips of the cornicles were reticulated, a character 
which separates pisi from many closely related forms. Doubtless 
this error on the part of Buckton led Sanderson to consider certain 
American species with reticulated cornicles as synonyms or varieties 
of pisi. In 1904 Pergande described a species under the name 
MacrosipTium tr'ifolii} TTe have had an opportunity to examine the 
type slide of trifolU Perg. and find it to be identical with pisi, and our 
determination has been verified by ^Ir. Pergande. Xotes on the 
1 Prof. Fred. V. Theobald (Theobald, Fred. V. The British species of the genus Macrosiphum, Passerini, 
Pt. II. In Jour. Econ. Biol., v. 8, no. 3, p. 139, fig. 46, Sept. 29, 1913) has described a new species imder the 
name J/. /r//"o/fi, overlooking the fact that the name is preoccupied. We therefore propose for this species 
Macrosiphum ihcobahUi n. n. It is distinguished from pisi, according to Theobald, only by the usually 
paler green color, the absence of sensoria on antennal segment III of the wingless female, and relatively 
thicker antennte, which are rather variable characters for this genus« "\A'inged forms were not observed 
by Theobald. It is not improbable that this vnU prove to be pisi. 
