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Indiana University Studies 
have been made heretofore. These galls, however, differ only 
in details of size, color, and their degree of hardness and there 
can be no objection on these grounds to considering the two 
as varieties of a single species. In first describing the form 
pubescentis Mayr (1881) suggested that (translating) : “D. 
pubescentis . . . should perhaps be considered only a 
subspecies of D. folii” — a suggestion which, if it had been fol- 
lowed, would have given us a better understanding of the com- 
mon ancestry of the two and of the geographic isolation which 
must be chiefly responsible for their preservation as genetic 
entitites. 
The variety folii occurs on Q. pedunculata and Q. sessiliflora 
thruout most of its range. In its more southern extension it 
undoubtedly occurs on Q. pubescens (acc. Straton 1894 and 
Connold 1902 in England, Houard 1914, Marcellia 13, in Cen- 
tral France, and particularly acc. Cotte 1910 in Provence). 
Further collections made in areas where both folii and flosculi 
occur on Q. pubescens should be studied to ascertain how much 
interbreeding may go on where the two enjoy neither host 
nor geographic isolation. 
As far as our records go, the variety folii reaches the Medi- 
terranean coast only in Provence, unless Oraffe’s record 
(1905) for Triest proves correct. There are no substantiated 
records for folii south of the Pyrennes or the Alps. Flosculi 
on the other hand does not get north of these mountain ranges, 
altho it does occur in a restricted Mediterranean strip in 
Provence, and farther east it extends thru Austria and Bo- 
hemia as far as the boundaries of German Silesia. It is nota- 
ble that insects of folii and flosculi in my collection are all 
readily separated by the characters given above except for 
the material which comes from Moravia, Bohemia, and south- 
ern Silesia. Among nearly four hundred insects of folii which 
I have from localities in Denmark, France, and Central Ger- 
many, not a single one shows appreciable variation toward 
pubescentis * But out of 21 adults from Moravia (Baudys 
coll.), one shows the radial vein and another the scutellum 
typical of flosculi . One of my three insects from Dresden 
(southern Silesia) has a distinctly bent tip to the radial vein. 
All of the Moravian material is unusually dark in color. A 
Mayr specimen (determined as scutellaris) from Vienna also 
tends toward flosculi in its wing venation. 
