MAPLE APHIDES. 417 
54. Psylla annulata Fitch. 
55. Siphonophora acerifolice Thomas. 
This plant-louse occurs on the soft maple {Acer dasycarpum) in Iowa, 
Illinois, and Missouri. 
56. Pemphigus acerifolii Riley. 
Living in abundant and long cottony excretion, on the under side of the leaves of 
Acer dasycarpum, causing them to curl, and exuding an abundance of thick and very 
glutinous " honey-dew." 
Winged female : Alar expanse 10 min . Head and thorax bluish-black. Abdomen 
black, covered with long cottony threads. Antennae reaching the wing-insertions ; 
annulations not conspicuous ; joints 3, 4, 5, and 6 somewhat contracted at base and 
apex ; apical unguis not perceptible ; joints 5 and 6 subequal ; 4 distinctly clavate ; 
3 as long as the two preceding together. Wings subhyaline, of a whitish tinge ; sub- 
costal vein and the inner margin of the stigma black ; oblique veins whitish ; stigma 
short and broad, not angled at the base of the stigmal vein, which starts from a little 
behind its middle, and is comparatively straight, thereby making the apical cell 
rather narrow. Terminal distances between the veins subequal, that between second 
discoidal and cubital somewhat greatest ; basal one-third of the cubitus hyaline, but 
not abortive, as it can usually be traced to its base, which is very close to that of the 
second discoidal ; bases of the two discoidals either approximate or quite contiguous ; 
discoidals of the hind wings proceeding connectedly from the subcostal vein. Larva 
with five-jointed antennae, and the promuscis extending beyond tip of abdomen. 
(Riley.) 
57. Pemphigus aceris Monell. 
Occurred on the under side of limbs of the sugar maple, enveloped in 
woolly matter, Peoria, 111., June. A comparison of about fifty speci- 
mens each of P. aceris and P. acerifolii shows that the antennal differ- 
ences between the two are quite constant. 
Winged female. — Head and thorax dusky, abdomen dusky, but appearing white 
from the abundant pulverulent matter. Antennae long, slender, the apex of the 
fourth joint reaching the insertion of the wings ; the joints subcylindrical, scarcely 
contracted at base, apical claw not perceptible ; fourth and fifth joints subequal, 
fourth joint not clavate, third joint less than the two preceding taken together. 
Wings subhyaline, subcostal and oblique veins brownish black. Stigmal vein arising 
behind the middle of the stigma. Venation closely resembling that of P. acerifolii, 
except that the base of the first discoidal is usually more remote from that of the 
second discoidal. Length 0.12 to 0.15 ; expanse of wings 0.20 to 0.22 inch. (Monell.) 
58. The gloomy scale. 
Aspidiotus tenebricosu8 Comstock. 
This species has been observed by Professor Comstock on the bark 
of the trunk and limbs of red or swamp maple (Acer rubrum) at Wash- 
ington, D. O. 
Scale of female. — The scale of the female is very dark gray, agreeing in color with 
the bark to which it is attached; the protuberance indicating the position of the 
exuviae is marked with a white dot and concentric ring ; in rubbed specimens this 
protuberance is smooth and black, in all cases the remainder of the surface of the 
scale is rough. The scale is very convex ; the exuvise are usually between the center 
5 BNT 27 
