THE PEA APHIS WITK KELATIOX TO FORAfiE CROPS. 
23 
Sexwparx. — What we have supposed to be wingless sexiiparje, 
that is, viviparous females which give birth to the sexual forms, 
dijBFer from the surmner wingless viviparous females only by a larger 
number of sensoria borne on antennal segment III. There is no 
positive assurance that these are sexupar?e but all of our mounted 
specimens showing this character were collected in September or 
later. Likewise^ wingless viviparous females, collected in Russia dur- 
ing September by Dr. A. Mordwilko and sent us by Dr. N. Cholod- 
kovsky, bear a similar number of sensoria. Six antennae of speci- 
mens collected at La Fayette, Ind., in October bear 10, 7, 8, 9, 13, 
and 16 sensoria, respectively, on segment III, and eight anteima) of 
specimens collected in Russia in September bear 21, 22, 14, 7, 9, 9, 
0, and 10 sensoria respectively, on segment III. 
Aberrant form. — In the fall it is not uncommon to find a form 
which has the hind tibia swollen and bearing numerous sensoria, a 
character pf the oviparous female, ])ut instead of eggs the body often 
contains living young. 
DESCRIPTIVE NOTES ON TYPE OF TRIFOLn PERG. 
The type slide of M. trifolii Perg. which we examined September 
5, 1911, bears the following data on label: ''7205 (Xectarophora) 
Macrosiphum trifolii n. sp. Perg. on clover, Charlottesville, Va., Apr. 
28, 1900." There are five winged viviparous females on the slide, 
the bodies of which are shrunken. The second branch of the median 
vein branches at a distance from the tip of the wing varying from 
one-half or less to three-eighths the distance from the tip to where 
it first branches, but usuall}^ the brandling is nearer to the tip than 
to the point where the media fii'st branches. Cornicles imbricatc^d 
over their entire length but more distinctly near tip; the tip not 
reticulated. From the balsam specimens the tips of the cornicles 
appear to have been dusky m life, the remainder concolorous with 
body. Measurements of the antennal segments, cornicles, and cauda 
were taken as follows: 
Antennae. 
n. 
III. 
IV. 
V. 
VI 
base. 
VI 
filament. 
Mm. 
^fTn. 
Mm. 
Mm. 
Mm. 
Mm. 
Mm. 
0.156 
0. 0()9 
0.678 
0.556 
0.574 
0. 243 
Broken 
.156 
.078 
.609 
.522 
.539 
Broken 
Broken 
.156 
.069 
.626 
.487 
.504 
.209 
0. 749 
.148 
.069 
.591 
.4S7 
(•) 
(') 
. 226 
(') 
.1.56 
.069 
.731 
.574 
.582 
.801 
.156 
.069 
.757 
.609 
.009 
. 22() 
.174 
.078 
.835 
.661 
. mi 
.243 
.iio"' 
.156 
.069 
.870 
.061 
.CM 
. 261 
.905 
. 156 
.069 
.mi 
.5,56 
.591 
.209 
.731 
.156 
.069 
.601 
. 556 
.582 
235 
.818 
1 Xot measureable. 
