April, '17] DAVIDSON: ^\t:stern plant lice 291 



and have in addition, at the base of the abdomen, two pairs of con- 

 spicuous yellow areas. The second generation matures about the 

 second week in April and the third generation about the beginning of 

 May. The nymphs are apparently not abundant and the single 

 winged specimen I have collected ma}^ be described as follows: 



Head, thorax, scutellum, sternal plates dark olive green, shining; antennae and 

 legs pale j^ellow hyaline, the two basal antennal joints dai'k olive green as the head; 

 eyes red, compound; pro thorax, wing insertions, abdomen j'ellowish-green ; cornicles 

 brown; Cauda pale green; wing veins brown, narrowly bordered dusky; beak pale, 

 apical third dusky; head evenly rounded in front as in apterae; eyes and ocelli 

 prominent. At the base of each antenna, intad, on the margin of the head is an 

 acute pale tubercle of about the size of the central ocellus. Antennas about half the 

 body in length, 5-jointed, III sub-equal to IV and V combined; beak reaches third 

 coxa?; thoracic lobes partly fused; wings carried horizontal, third discoidal vein un- 

 branched in one wing and with a branch at apex in the other; hind wing with one 

 discoidal; cornicles pore-like; cauda small, globular; abdomen robust. Measurements 

 (balsam mount); length body .75 mm.; width body .36 mm.; antermse .39 mm. 

 Date of collection, May 16, 1915. 



The above-described individual was submitted to Mr. A. C. Baker, 

 U. S. Bureau of Entomology, Washington, D. C. Mr. Baker has 

 pointed out the following differences between it and European speci- 

 mens of V. dryophila in the U. S. National Museum collection: Typi- 

 cal dryophila has four circular sensoria and about 12 prominent hairs 

 on antennal III, while the Cahfornia specimen has no sensoria and not 

 over 3 hairs; the thorax of typical dryophila is without any indication 

 of lobes, whereas the California individual has the thorax partly divided 

 into lobes. 



The spring colonies of apterse are greedily attended by ants and from 

 their very gregarious habits fall easy prey to predators. After May 

 the only forms remaining are the young sexuals which are deposited 

 by the alatse of the third generation during May. The spring col- 

 onies feed both on the stalks and on the lower leaf surface but the 

 sexes only in the latter location. The sexuals are often quite abun- 

 dant and are not so gregarious as the spring forms. Although 

 deposited in May they do not cast their first skin until September and 

 are not mature until the latter part of November. 



The full-grown insects are of a pale lemon color with greyish antennae and legs, 

 and the cornicles appear as brown-rimmed pores. They are armed with thick 

 spines. The eyes are simple, of 3 facets. The last antennal joint is markedly 

 longer than the penultimate and about as long as III. It bears a fringed sensorium. 

 The beak reaches to the second coxae. The male measures about .51 mm. by .23 mm., 

 antennae .21 mm., the female about .85 mm. by .44 mm., antennae .23 mm. After 

 mating the female deposits a single egg in the axils of the buds. This egg is oval, 

 black, lightly covered with silvery filaments previously noticeable on the sides of 

 seventh and eighth abdominal segments of the female. 



