IOWA ACADEMY OF SCIENCES. 
83 
Lasius latipes and flavins examined on numerous occasions, but 
not a Scliizoneura corni could be found. Even some artificial 
transfers proved a failure. 
The latter part of August a winged specimen of Scliizoneura 
corni was found on cornus. The peculiar conditions to which 
this species of Scliizoneura was subjected, viz.: a warm spell in 
March, followed by freezing weather, and then the drouth of a 
midsummer, nearly annihilated this Aphid. 
Although numerous descriptions of some stages of Scliizon- 
eura corni have been published, it seems desirable for sake of 
comparison to give full description of the root forms*. 
Scliizoneura corni root-type from perennial grasses, Sep- 
tember 23d. 
Adult winged viviparous form, from: Andropogon farcatus: Expanse of 
wings, 6.61mm. Length of body, 2.25mm. Width, 1.22mm. Length of 
antennae, .87mm. (Joint I, .087mm; II, .06mm; III, .3mm; IV, .11mm: 
V, .13mm; VI, with unguis, .17mm.) Eight sensoria on joint three, two 
each on IV and V, one on VI. (It is doubtful if the roughened areas near 
apices of IV, V and VI are true sensoria, if not, then IV and V have one 
each.) Antennae and head dusky to black, membrane of articulations, yel- 
low; prothorax and margin of thorax, dusky; callosities, black; abdomen, 
yellow. A dusky brown patch covers the fourth, fifth and sixth, and some- 
times base of third segments; a band of same color extends across the 
seventh and eighth segments, also spots of the same color occur on the con- 
nexivum. Eyes, brick red; wing insertions, yellow; distance between points 
of insertion of first and second discoidals and base of cubital aiDproximately 
equal. The latter obsolete at base, furcal starting about midway between 
base and apex. Stigmal with slight compound curve. Stigma .435mm x 
.18mmt. Legs, dusky; apical portion of femora and tibiae darker. 
After migrating and depositing pseudova the yellow colors 
are not so marked, while the dusky markings are darker. The 
shrinking of the abdomen causes the dusky patch to appear to 
cover the whole dorsal surface. 
*Since plant lice are subject to slight variations in color markings, wing venation 
and sensoria markings, though probably no more than other insects, if examined with 
compound microscope, and as many species are covered with pulverulent and floccu- 
lent secretions, or with hairs, it would be a help, and avoid some error in comparison 
if authors would stace under what conditions the descriptions are made. If examined 
with naked eye or hand lens, and held so the light is reflected, the pulverulent matter 
and hairs produce one color effect; if held between the observer and the light, enough 
light is transmitted through the thin body walls to give a different effect. If the spec- 
imens are mounted in balsam, and examined with compound microscope, different 
shades of color will be produced from those noted when examined before mounting. 
These latter will vary according to whether transmitted or reflected light is used. 
Unless otherwise stated the color markings as given are from mounted specimens with 
reflected light, and the measurements from transmitted light. 
+The length of the stigma as given means distance from point of union of costal 
and subcostal veins and apex. 
