Page:The Gall Wasp Genus Cynips.pdf/118

 coll.), and mature adults may be found in the galls before that month is over (acc. Beyerinck 1883 and Kieffer 1901; also material from Moravia, Baudys in Kinsey coll.) or in October (acc. Adler 1881). As with nearly all the other species of the whole genus Cynips, the adults delay their emergence until late fall to early winter. The galls fall to the ground with the leaves late in October or early November, by which time the insects have chewed a passage thru to the epidermis which, however, is not broken until actual emergence occurs.

Emergence varies in different localities from October to March, tho the bulk of it occurs everywhere in the early winter. Schlechtendal (1870) records September and October emergence, and Cameron (1893) also records October emergence. Paszlavszky gives November as the time for Hungary (acc. Kieffer 1901). Kieffer (1901) gives late November and early December—no later—for Lorraine. Beyerinck (1883) also says November and early December for Holland. Adler (1881) records December and January with occasional emergence in February or even March, in Germany; and Mayr (1882) notes late winter emergence in Austria. There is a December 20 record for England (acc. The Ent. 4:77). The material which I have from Denmark (Hoffmeyer coll.) bears dates of October 20, November 11, 19, 23, December 5, 7, 10, 17, 21, 25, 27, and January 3, 8, 9, 11, and 14. Fitch (1876) recorded emergence from January 1 to 21 on the Isle of Wight. Bignell (1897) gives January 18 to 25 for his part of England.

Several observers have noted that this insect does not emerge from the galls until the temperature is lowered to near the freezing point, and emergence on dates after the middle of December are apparently for stray adults which were frozen before they effected their escape from the galls in early winter and which later emerged, as Adler (1881) noted, in the thaws that break into winter's régime. Beyerinck (1883:28) found that insects cut from galls before their normal emergence time would not lay eggs. The same author found that in a warm room emergence might be delayed until January, which is in accord with my observations on the fall generations of American Cynips. Paszlavszky (1883) instituted some exact determinations of the temperature effects on this insect's activities, with the following results:

At 8°C insects were inactive, apparently frozen