us our most northern record for an oak-inhabiting cynipid. Upon examining the material which Dr. Forsius was good enough to send me, I find that most of it is distinct from the typical material of Central Europe. I am dedicating the new variety to Dr. Forsius to whom we are indebted for much information on the northern distribution of many other Hymenoptera. I understand that oak does not extend north of the very southern end of Finland, and we are fortunate in having cynipid material from that area.
Forsiusi insects are far more distinct from the Central European longiventris than longiventris is from the Central European folii or the Mediterranean pubescentis (insects). The galls, however, prove the relation of forsiusi to longiventris, their origin from a common stock, and perpetuation by isolation in what seem to be two distinct faunal areas of Europe.
Of the ten insects I have from Lojo, Finland, one is intermediate between forsiusi and typical longiventris. Three insects from Runsula in southwestern Finland approach typical longiventris. In a series of 88 adults of this species which I have from Denmark (Hoffmeyer coll.) there are five insects which approach typical forsiusi, a single insect which seems intermediate between forsiusi and longiventris, and 82 insects which are the Central European longiventris. There is apparently some transition area between the more northern and Central European faunas, but this probably does not extend south of Denmark.
Forsius records the occurrence of these galls in September, and the emergence of the adults on October 31 and November 1. This emergence is earlier than that for the typical longiventris. This matches our experience with many American Cynipidae among which there are some cases of the northern varieties emerging as much as two and a half months earlier than the corresponding varieties of the southern United States.
Cynips (Cynips) divisa Hartig
agamic and bisexual forms
