700 Pomona College Journal of Entomology 



Bibliography 

 lyoy yVw/)/i(V».s- nidirirola Kssij.-. 1'. ('. Jr. Knt., 1.. pp. 8-10. original 



description. 

 !<)()<) Trifidaphis radicicola (Essig) Del Gutrcio. Rivist.i fli Patal. Vcsrctali-. 



Anno. Ill, p. StVi. Placed in new genus. 

 I <)()<) T. rndicicola Essig Del Giureio-liaker, P. C. Jr. Ent.. I.. \^\^. lS-l'i. 



Translation of Del Guereio's article, 

 lyio T. radicicola Essig Del Guereio-Wilson. Ent. News, XXI, p. 15,'5. List 



of Genera. 

 1,<)1() T. radicicola Essig Del Guercio-Essig, P. C. Jr. Ent., II. ])p. '283-'28->. 



Wing variations, 

 lyil T. radicicola Essig Del Guereio-Essig. P. C. ,Jr. Ent.. pp. lll-lSS. 



Host plants and synonymy. 



Pemphigus californicus Davidson 

 (Tiie Woolly Plant Eouse of the Buttercup) 

 ]f)in Pcmphiiius ranunculi Davidson, Jr. Ec. Ent. Ill, pp. ST^-.S?."?. Orig- 

 inal descrii)tion. 

 lyil Pemphigus californicus Davidson. ,Ir. Ee. Ent. IV, p. HI-. Renamed. 



WINGED VIVIPAROUS FEMALE (EigUre 223 A) 



Length of body without flocculence 2.6 nmi.. width of mesothorax 0.9 mm., 

 width of abdomen 1.1 mm., wing expansion ().7 mm. Bodii — Covered with a long 

 white or bluish-white flocculence. Naked body of the tyjjical Pemphigus shape, 

 thorax little wider than abdomen. Prevailing color — With the flocculence white 

 and black, witliout flocculence, black head, and thorax and dull green abdomen 

 with brown apjiendages. Head — Broad base and well rounded in front between 

 the antennip, nnich wider than long, with two compound and three ocellar eyes, 

 black. Ei/es — Compound eyes very dark red with a marginal terete tubercle on 

 the after part; this tubercle is composed of two small ocelli (Figure 223, 2). 

 This is till' only instance of this kind I have ever noticed and a character not 

 mentioned by Davidson in his description. Antennae — (Figure 223 C, E, F). 

 Arising from near the sides of the head, bases widely distant, reaching to second 

 abdominal segment ; usually dark throughout ; three ajjieal articles with lighter 

 bases, all light at articulations, apical half imbricated, with very few short hairs; 

 article leiigtlis as follows: I, 0.12 mm.; II, 0.12 mm.; Ill, 0.t,5 mm.; IV, 0.19 

 nun.; V, 0.2,') mm.; VI, 0.21 mm. (unguis or spur 0.03 mm.); total 1.3 t nun. 

 Articles I and II usually coequal. III longest, nearly as long as IV and V together 

 and longer than IV and VI together, IV shorter than VI, V longer than either 

 IV or VI, and more than twice as long as eitlirr I or II, VI, with base a])])rox- 

 im;itily six times as long as the unguis. Articles traversed by numerous long 

 transverse sensoria which are very unevenly distributed. Ill has from nineteen 

 to twenty-five, more often with twenty-one; I\'. four to eight. In examining 

 eight articles there were to be found one witli four, one with five, two with six, 

 three with seven and one with eight; article V, with from one to four, three and 



