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 lOmm. 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.— Yle'A^. 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 tenebrieosus 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. 0. 



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 exuviae are usually between the center 

 5 ENT 27 



