18(52.] IMI 



Additions and corrections to the paper entitled: 

 "On the CYNIPID^ of the North American Oaks and their Galls." 



BY BARON H. OSTEN SACKEN. 



Since the publication of my paper on the ([i/nqndse, of the North Amer- 

 ican Oaks (Prcc. Entoni. Soc. Phihi. Oct. ISOl), I have had occasion to 

 make some additional observations, which serve to conipletc and often to 

 correct, the statements of that jiaper. 



It ve(|uires a particularly favorable situation to be able to pursue obser- 

 vations of this kind with some hope of attaining a certain completeness. 

 My position in Washington, although aifording me some facilities, did not 

 always allow me to attain the accuracy which I desired. 3Iy removal to 

 New York will probably deprive me for a long time of any opportunity 

 of pursuing my observations. I prefer therefore, to publish now those I 

 have on hand, following the conviction, already expressed before, that ob- 

 servations of nature should be made known without waitiii"- too lontr for 

 their further accumulation. The reader favorably situated may perhaps 

 find among mine, incomplete as they are, some useful hints and suggestions. 

 The subject is so extremely interesting and attractive that it deserves more 

 attention than has been paid to it, not only in this country, but even in 

 Europe. 



All the observations, recorded below, have been made in Washington, 

 unless otherwise mentioned. 



Those who have paid any attention to the nomenclature of the oaks of 

 this country, are acquainted with the difficulties attending the recognition 

 of the species, chiefly of the red-oak group, if this recognition is to be 

 based upon single leaves or even young trees. Thus I became aware after 

 the publication of my paper, that the tree which I had called the red-oak 

 (^Q. ruhrci) was, hi moat cases ^ the scarlet-oak I^Q. coccinca), which seems 

 to be more abundant around Washington than the other. Most of the 

 galls, therefore, mentioned as found on the red-oak, belong very probably 

 to the other species. In some cases, I have been able to verify this fact, 

 last spring. Other cases, however, are still doubtful. 



I. Additions to the paraoraphs on the Oak-Apple (Jalls. 

 ( 1. c. No. 1 and No. :>. p. o(] and 58.)* 



At the time of my })revious jaiblication, T todk for the gall of ('. roii- 



* This paragraph supersedes the NN 1 and .3 of my former paper, except the 

 descriptions of C. q. acicu/ata and Synophriis /(criventris (1. c. p. 5(; and .i7), which 

 have not boon loprodiict'd liere. 



