September, 1941 
pale at extreme apex. Pronotum blackish, 
calli and central area of disk pale; scutellum 
black, lateral margins more or less pale; 
sternum, pleura and ostiolar peritremes 
black. Hemelytra mostly black; basal one- 
third of embolium and eorium, and adjacent 
area of clavus, pale; cuneus pale, but apex 
distinctly blackish. Legs pale to yellowish; 
base of hind coxae, line on apical half of 
dorsal margin of femora, and two rows of 
spots just beneath, black. Venter blackish, 
more or less pale on sides. 
Known DiIstriBpuTIOoN.—Colorado, IIli- 
nois, Massachusetts, Michigan, Minnesota, 
New York, Nova Scotia, Quebec. 
An extremely light form of this species 
in which the cuneus is uniformly pale or 
yellowish, and in which broad, pale areas 
are sometimes present on the dorsum, is the 
variety albocuneatus Knight (1923d, p. 438). 
Those specimens of this species having the 
scutellum entirely black may be designated 
variety fraternus Uhler (1895, p. 51). This 
variety was originally described as a species, 
but the examination of a large amount of 
material, from Colorado as well as the east- 
ern states, has led to the conclusion that 
fraternus is nothing more than a variety of 
obscurus. In Illinois material, intergrades 
occur between all these varietal forms, which 
are found together in the field. 
Illinois Records.—Fifty-four males and 
60 females collected June 2 to Sept. 13 are 
from Algonquin, Antioch, Elizabeth, Fox 
ake, Frankfort, Galena,” Mason City, 
Rockton, Rosiclare, Savanna, Starved Rock 
State Park, Urbana, Volo, Waukegan, Zion. 
Plagiognathus negundinis Knight 
Knight (19294, 
Plagiognathus negundinis 
fe 203). 
This species is allied to annulatus Uhler, 
but differs in having a longer second anten- 
nal segment which, in the male, equals or 
slightly exceeds the width of the pronotum 
at its base. 
Mave.—Length 4.00, width 1.36. Head 
width 0.72, vertex 0.37. Rostrum reaching 
to middle of hind coxae. Antennae black; 
first segment, length 0.27; second, 1.20; 
third, 0.75; fourth, 0.35. Pronotum, length 
0.62, width at base 1.17. General color 
black, vertex pale. Legs orange yellow, hind 
femora with a row of four or five black 
spots on antero-dorsal line, also one spot on 
median line of anterior face at middle of 
KNIGHT: PLANT Bucs, or Miripagz, or ILLINOIS 33 
apical half, sometimes with two or three 
smaller dots, and two subapical black spots 
beneath; tibiae yellow; knees, spines, and 
spots at bases of spines, black. Clothed with 
recumbent, yellowish to dusky brown pubes- 
cence. 
FEMALE.—Length 3.80, width 1.40; very 
similar to male in pubescence and coloration. 
A variety, fulvotinctus Knight (1929d, 
p. 264), is known from lowa; it differs 
from the typical negundinis in that the em- 
bolium, basal half of corium, outer margin 
of clavus on basal half, and basal half of 
cuneus are pale to orange yellow 
Foop PLant.—Box Elder (4dcer negun- 
do). 
KNOWN 
Minnesota. 
Illinois Records.—Fox Lake: June 10, 
1936, Ross & Burks, 14. GALENA: June 
307 1932 Dozier NalViohr, 14s los. Haq 
WAM NAs. WVlay. ol 1933.56 O- Mohr, 273, 
SOP OOUAWRAs une 15991932, Ha 
Dozier, 29. PuTNAm: June 2, 1933, Mohr 
& Townsend, 2¢,19. Urpana: June 20, 
1932; Frison & Ross, 19. Voto: July<8, 
1932, Ross, Dozier & Mohr, 1 ¢@. 
DIstriBUTION.—lllinois, Iowa, 
Plagiognathus brevirostris Knight 
Knight (1923d, 
Plagiognathus brevtrostris 
p. 441). 
The general aspect of this species is very 
similar to that of obscurus var. albocuneatus 
Knight, but it is larger and more elongate 
and the cuneus usually is tinged with ful- 
vous; it is distinguished by the short ros- 
trum, which does not reach the hind margins 
of the middle coxae. 
Mave.—Length 4.60, width 1.80. Head 
width 0.79, vertex 0.37. Rostrum reaching 
middle of intermediate coxae. Antennae, 
first segment, length 0.35; second, 1.43; 
third, 1.00; fourth, 0.54. Pronotum, length 
O63," width™ at. bases 1.265." General. color 
black, moderately shining, embolium and 
basalihaliot-cormunim pale. dark color «tre- 
quently invading apical half of embolium, 
sometimes pale color extending along claval 
suture to anal ridge; cuneus pale, usually 
tinged with fulvous; apex sometimes dusky. 
Legs black, femora frequently with rather 
broad, pale area at base; tibiae pale; knees, 
spines and spots at base black. 
FEMALE.—Length 4.00, width 1.89; short- 
er and more robust than male; legs with 
broader pale areas. 
