Kinsey: Shidies of Cynipidx 



9 



cubital cells; anterior margins rather short-ciliate; veins brown; areolet 

 moderately large; cubitus not reaching the basalis; radial cell moder- 

 ately short, open; the second abscissa of the radius somewhat curved, 

 the tip parallel with the margin for a short distance; first abscissa 

 sharply angulate at almost 90°, with hardly any projection. LENGTH: 

 3.0-5.0 mm. 



GALL. — Large, globose to reniform, smooth, twig gall. Mono- 

 thalamous, or polythalamous, containing from one to a dozen larval cells. 

 Irregularly rounded, ovate, ellipsoid to reniform, all sizes, up to 65. mm. 

 in diameter by 113. mm. long; the surface smooth, sparingly, shallowly 

 roughened; reddish to yellow and brown. Internally more or less filled 

 with compacted, soft, crystalline, brown, yellow, or white material, 

 woody from the point of attachment to above the center of the gall; 

 the larval cells oval, averaging 4.-5. mm. long by 3. mm. wide, more or 

 less radiantly in the woody tissue, toward the center of the gall. Later- 

 ally, on twigs of several white oaks. 



RANGE. — From the Mexican border of California to Washington. 



The most apparent differences between the varieties of 

 this species are those of color and size. That we may have 

 underestimated the constancy of these characters with some 

 species is indicated by the absolute correlation of these dif- 

 ferences with the physiologic differences and geographic dis- 

 tribution. 



An astounding structural characteristic of one of the 

 varieties is the complete parapsidal groove; the other va- 

 rieties have the groove terminating very distinctly midlength 

 of the thorax. 



The occurrence of variety calif ornicus upon two hosts 

 without consequent variation, and the possible occurrence of 

 fructiforwis upon two more distinct hosts (as discussed under 

 that variety), offer data concerning the non-influence of hosts 

 upon the insect, and further confirm the idea that the gall is 

 specific for the insect producer, without evidence of direct 

 host influence. 



The most important problem which this species may illu- 

 minate is that of the nature of alternation of generations. 

 As discussed for each of the varieties, the northern forms 

 quite certainly have alternate generations, but in the south- 

 em form the close concurrence of emergence dates and the 

 appearance of fresh galls make it seem possible that there 

 is no alternation of generations in the perpetually warm cli- 

 mate of southern California. If this is demonstrated it will 

 confirm my opinion previously expressed (1920, Bull. Amer. 

 Mus. Nat. Hist., XLII, p. 372) that alternation of generations 



