PfiRGANDE — NORTH AMERICAN fHVLLOXERlN^. 261 



3M6.pumila, and also to some extent on the twigs of shrubs grow- 

 ing in the District of Columbia and in Maryland. The infested 

 leaves, frequently become very much distorted, when the ribs or 

 veins turn brown or yellowish-brown, on account of which many 

 of the leaves as well as numbers of the twigs dry up. 



It seems rather remarkable that the majority of the immature 

 stages of the insect, inhabiting the under side of the leaves, are 

 of a pale yellow or almost white coloring, bearing small protu- 

 berances, whereas the majority of those on the upper side, as a 

 rule, are bright orange and provided with long and slender 

 tubercles. It appears, also, that one or the other form inhabits 

 certain shrubs quite exclusively, while again both forms may 

 occur on the leaves of others ; which possibly may indicate two 

 closely related species. 



On examining the females of the two forms mentioned above 

 I find that all those belonging to the pale form are provided with 

 very short protuberances, which, on the abdomen, become quite 

 rudimentary, whereas those belonging to the orange form bear 

 long protuberances, similar to those of the pupae. I consid^er, 

 therefore, the pale or yellow form as the species described by 

 Haldeman. Future studies, from the earlier stages to the 

 migrant and sexes of the two forms, may reveal the presence of 

 two related species upon Castanea, which may justify the adop- 

 tion by me of the name of Phylloxera spinifera for the orange or 

 spiny form. 



Phylloxera rileyi Riley. (Licht. Mss.) 



PI. x:x., figs. 151-154. 



Stem-mother. — Length about o.6'""-; diameter across the 

 thorax about 0.3"""-. Color dark greenish-yellow to dark brown, 

 the protuberances almost black, the eyes dark purple or black, 

 antennse and legs dusky. The antennae are long and slender and 

 almost one-third the length of the body; the third joint is 

 extremely slender, very slightly clavate with numerous sharply 

 defined serrations ; the sensorium small and elongated oval. The 

 fleshy protuberances of the body are abnormally long, especially 

 the dorsal ones, which gradually diminish in length towards the 

 end of the body, and wanting on the last two segments; those 



[Proc. D. a. S., Vol. IX.] 32 [Dec. 30, 1903.] 



