THE PEA APHIS WITH RELATION TO FORAGE CROPS. 
3 
pisi. More rec(Hitly has come a contribution from Prof. Fred. V. 
Theobald (11, 12) who considers gei and ulmariae as distinct species, 
thus corroborating the general conclusions of the two eminent Rus- 
sian entomologists, Cholodkovsky and ^lordwilko. Theobald sepa- 
rates these large green psi-like Macrosiphums into two groups ac- 
cording to the structure of the tip of the cornicle: (1) Those with the 
tip imbricated, containing pisi Kalt., loti Theob., and trifolii Theoh., 
and (2) the group of closely related species with the tip of the cor- 
nicle reticulated, including ulmariae Schr., gei Koch, and stellariae 
Schr. Further, he is of the opinion that ononis Koch is distinct 
from pisi. Our own studies lead us to follow Mordwilko's conclu- 
sions. Schrank's description of ApMs ulmariae certainly seems to 
indicate that he was dealing with a true Aphis and not a Macrosiphum. 
In 1782 Moses Harris, in his ' 'Enghsh Insects, " (1), figures an aphis 
which he calls Aphis pisum and gives a nondescript description. 
Theobald (12) has placed this species as a synonym of pisi, but there is 
nothing excepting the specific name to link it with the aphidid under 
discussion and it must therefore be placed as a possible synonym of 
irisi but not in the sense of having priority. 
Ill 1841 Sir Oswald Mosley (4) describes Aphis lathyri as foUows: 
8th Species: Aphis lathyri. — On the Sweet Pea beneath the leaves; colour green, 
becoming when old of a dark purple; antennae longer than the body; abdomen 
"acuminated, with tubercles nearly extending to the extremity. 
There is little doubt but that this description referred to pisi, but 
even with two years' priority the name lathijn can hardly take pre- 
cedence over the weU-estabhshed name pisi and must be placed in 
the same category as Harris's pisum. 
The correct name which should be adopted for this insect is still 
somewhat questionable, but at this distance we, in .^Sjnerica, must 
follow largely the researches of European aphidologists. M. pisi 
Kalt. must for the present be considered as having priority, although 
further researches may prove Aphis onohrychis B. de Fonsc. to be 
identical, this species having two years' priority over pisi, as stated 
above. In this connection Mordwilko (10) says: 
The same species of plant louse [refen-iug to pisi] was apparently described two 
years earlier (1841) by Boyer de Fonscolombe and named Aphis onohrychis, having 
been found on Iledysarum onohrychis. However, it is still premature to regard these 
two names as synonyms. 
Walker, Buckton, Ferrari, Schouteden, Theobald, and others Inive 
made onohrychis a synonym of pisi hut none has given sufTicient evi- 
dence to support this conclusion. Authors discussing a plant louse 
on pea under tlie name ulmariae doubtless had in mind J/, pisi, 
since it seems to have been fully proven that the true ulmaiiae does 
not feed on the hosts recorded for pisi. Further, we must accept 
