I conclude the foregoiuji- descriptions of oak-apple galls, by a synopsis 

 of those at present known to me. I omit the species growing on the black 

 oak, as I know it but imperfectly. 



With the spongy substance inside. 



Shell thick ; spongy substance very dense. 



Broad and rounded on the top ; surface smooth 



and glossy ; autumnal gall on Q. tinctoria : C. q. aciculata 0. S. 



Attenuated and pointed on the top ; surface 

 more or less opaque, as if powdered or dust- 

 ed; vernal gall on Q. tinctoria: C. q. spongifica 0. S. 



Shell thin and brittle ; spongy substance less dense. 

 Rounded, almost globular; surface glossy; ver- 

 nal gall on Q. coccinea : C. q. coccinese 0. S. 



With the filaments radiating from the kernel to the 

 shell ; the latter thin and brittle. 



More or less globular, not attenuated towards 

 the basis ; surface glossy ; vernal gall on Q. 

 coccinea (or Q. )-nhra) : C. q. inanis 0. S. 



Somewhat lemon-shaped, that is, attenuated at 

 both ends, with a distinct nipple on top; per- 

 haps a variety of the preceding, as it occurs 

 apparently on the same kind of oak? Gall-fly unknown. 



Perfectly globular, smooth, smaller than all the 

 preceding galls, not drab, but more reddish- 

 yellow when ripe; shell although thin, but 

 harder; filaments on the inside more dense 

 and silky ; autumnal gall on Q. ohtnsilnha : C. q. centricola 0. S. 



II. GrENERAL REMARKS ON THE OaK-ApPLE GaLLS. 



The foregoing chapter records my recent observations on the oak-apple 

 galls of this country. These observations being, however, yet incomplete, 

 leave open several questions to which I now call the attention of future 

 observers. Such questions are : — 



1. Are Cynips q. inanis, C. q. coccineoe and C. q. spongifica one and the same species ? 



2. Have the gall-flies of the oak-apples one or two yearly generations? 



3. The question of the sexes. 



