38 A finals Entomological Society of A merica \\o\ .IT. 



in a row and the usual larger one at distal end of V, a single large seiisorium with 

 several smaller ones near its border, at distal end of base VI. (PI. VI, iig. 27.) 

 Wings with the first and second discoidals branching slightly nearer to the mar- 

 gin than in the viviparous female, this character being more variable in the 

 latter. 



Measurements [from specimens in alcohol and balsam]: — The measurements 

 for different individuals differs considerably in some cases, but the comparative 

 lengths are quite constant. Length of body, 1.79-2.36 mm.; width, 0.61-0.89 

 mm. ; length of wing, 2.61-3.29 mm. ; width, 0.98-1.18 mm. ; expanse, 5.75-6.50 

 mm.; antenna, I, 0.11; II, 0.07; III, 0.56-0.75, av. 0.67; IV, 0.44-0.63, av. 0.53; 

 V, 0.47-0.59, av. 0.535; VI, base, 0.13-0.145, av. 0.14; VI, filament, 0.99-1.26, 

 av. 1.12; average total, 3.175 mm.; cornicles, 0.55 mm.; style, 0.22 mm.; hind 

 tarsus, 0.15 mm. 



Egg: — Pale greenish or greenish yellow when first laid, and later changing 

 to jet black. Elliptical oval, measuring 0.64 mm. in length and 0.31 mm. in 

 width. 



The Ornamental Currant Macrosiphum. 

 (Macrosiphitm cynosbaii Oestlund.) 



The winged form of Macrosiphiim cynoshati was first described 

 by Professor Oestlund, it having been collected in Minnesota in 

 1887 on Ribcs cynoshati. It has not since been reported in the 

 literature as occuring elsewhere. 



This year (1908) it was very common and in some localities 

 quite injurious to the ornamental currants in Chicago parks. 

 It did not appear in injurious numbers until the first of August, 

 at which time only the wingless forms were present, and these 

 densely colonized the tender terminal twigs, infesting all parts, 

 but particularly tips of the twigs, or, when present in abundance, 

 the under sides of the leaves also, and in sufficient numbers to 

 curl them more or less. Winged forms were first found in these 

 colonies September 3. Usually either the common brown ant 

 {Lasius niger var. americaniis) or the black ant (Formica fused) 

 was in attendance upon the plant-lice. 



The sexual forms of this species were first found on these 

 same bushes October 5. at which time they were observed pairing. 



DESCRIPTIONS. 



Winged viviparous female [fro:n specimens collected in Chicago, 111.. Aug- 

 ust 10, and September 3 and 1 1, 1908]: — Head dusky with distinct and approxi- 

 mate frontal antennal tubercles and (i or 8 subcapitate hairs projecting cephalad 

 from the fore border. Antennae black, excepting the two dusky basal segments, 

 and a fine pale ring on III at joint of II and III; sparsely covered with hairs 

 which are more or less subcapitate; 30 to 43 tuberculate, circular sensoria, irreg- 

 ular in size and arrangement, placed the entire length of III, occasionally a single 

 one on IV, the usual sensorium at the distal end of V and one at apical end of 

 base VI with about 6 smaller ones beside it ; total length about one half longer 

 than the body. III almost twice longer than IV and a little more than one 

 fourth shorter than VI, IV and V, subequal, IV usually very slightly the longer, 

 base VI very short, it being subequal to I, filament VI about three times V. 

 (PI. VII, fig. 30.) Eyes dark red. Beak reaching slightly beyond the coxaj 

 of the hind pair of legs. Thorax pale green excepting the shield, which is pale 



