New York Agricultural Experiment Station. 483 



Descriptions and nates on life history. — The writer's attention 

 was first called tol this species early in June. 'At this time most 

 of the plum trees in the Station orchard were very badly infested 

 with this and other species of plant lice. Most of the lice of this 

 species were wingless and were present in all stages of develop- 

 ment. Pupie and winged forms were much less numerous. 



The larva. — The very yoiins? larva of average size measiu'os about 0.5 

 mm. in length. The lateral margins of the body are nearly, parallel, but 

 the body is usually slightly broader near the posterior extremity. The 

 general color is pale green with a slightly bluish tinge. The antennse are 

 six-jointed. Joints I, II, are shorter and sub equal in length. Eyes red, 

 legs stout, nectaries about as long as thick. The larvse, like the mature 

 lice, are covered with a bluish white powder. (Plate XXVII, fig. 1.) 



Apterous viviparous female. — Size of body 2.67 mm. by 0.99 mm. General 

 color pale or yellowish green, with slightly darker green mottling. A 

 medio-dorsal line of darker green, widest at about the middle, extends 

 from the head to the cauda. Eyes dark reddish brown. All appendages 

 nearly colorless or vei*y light green, with the exception of the anterior 

 half of the fifth and the entire sixth joints of the antennte, the tips of the 

 posterior tibise and the tarsi, which are dusky. Rostrum reaches nearly 

 to the second coxse. Antennae slender, about two-thirds length of body. 

 Joints III, IV and V sparsely tuberculated. Length 1.77 mm. Joints I, 

 II and VI shortest (III, 0.45 mm.; IV, 0.3 mm.; V, 0.25 mm.; VI, 0.125 

 mm.; VII, 0.45 mm.). Nectaries dusky; very short, 0.09 mm. in length, 

 about half as broad, and slightly restricted at base. Legs slender, cauda 

 prominent, slightly curved upward, 0.18 mm. in length by 0.12 mm. at 

 base, tapering toward the tip and furnished on either side with two slen- 

 der backward curved hairs. (Plate XXVII, figs. 5 and 6.) 



The apterous females were found on the native plums in the 

 Station orchard until the latter part of September, when only an 

 occasional individual could be found. 



Winged viviparous female. — Body more slender than apterous female. 

 Size of body 2 mm. by 0.74 mm. General color the same as the apterous 

 female. Head and prothornx usually somewhat darker green. Antennae 

 slender, slightly dusky with the exception of the basal third of the third 

 joint, which is pale green. Prothorax and thoracic lobes darker green. 

 Apical third of femora and tibiae, entire tarsi and nectaries slightly dusky. 

 Abdomen pale yellowish green with four to six triangular medio-dorsal 

 green marks ranged transversely. Front of head not conical. Measure- 

 ments of antennae about the same as in apterous female. Wings hyaline, 

 expanse 6.9 mm., veins yellowish green; stigma uari-ow. Nectaries and 

 cauda as in apterous viviparous female. (Plate XXVII, figs. 3 and 4; 

 pupa shown at fig. 2.) 



