8G 
Indiana University Studies 
late; the legs often darker in some small part; the wings at least rela- 
tively longer than in the female; the spotting in the cubital cell lighter 
or heavier than in the female; length slightly greater than in the female, 
the legs apparently longer than in the female. 
GALL OF AGAMIC FORMS. — Usually monothalamous (polythala- 
mous in pezomachoides) . Fundamentally spherical tho often much dis- 
torted in surface outline. The thin lining of the larval cell constitutes 
the nutritive layer; the cell wall (lacking in most of Acraspis) consti- 
tutes the protective layer; the bulk of the gall (except in Acraspis) is 
made up of a thinly or densely fibrous or a more compact parenchyma 
layer which holds the larval cell centrally and, in a few species (includ- 
ing all of Antron) , contains a second, unoccupied cavity; an outermost 
hardened layer (constituting the bulk of the gall in Acraspis) is the 
collenchyma layer; and the epidermal layer is usually naked or finely 
pubescent, in Acraspis becoming contorted into a faceted surface some- 
times coated with long spines or wool-like processes. Attached by only 
a small point (and therefore easily separable) on a main vein, usually 
on the under surface (less often on the upper surface, rarely on the 
petioles or young twigs) of leaves of white oaks; known from every 
group of white oaks that occurs in the regions inhabited by these insects. 
GALL OF BISEXUAL FORM. — Monothalamous. A small, thin- 
walled, hard-shelled, largely naked, roughly egg-shaped or simple seed- 
like cell; or a larger thin-walled, more succulent, irregularly bladdery 
capsule; in either case without well differentiated layers of tissue or 
unusual epidermal development and without a differentiated larval cell 
except the central cavity of the gall; always within young buds, often 
completely enclosed by the unopened bud; closely connected to the young 
or older twigs or (in adventitious buds) on the bark of the older trunks; 
on white oaks of the same species which harbor the agamic generation 
of the insect. 
RANGE. — Known from North America from southern Canada to 
central Mexico, from Europe wherever oaks occur, and from the borders 
of Asia and Africa on the Mediterranean Sea; not known, but to be 
expected from the rest of Asia wherever oaks occur. Figure 7. 
GENOTYPE. — Cynips folii Linnaeus. Designated by Westwood, 
1840, Generic Synop.: 56. See the discussion under the European sub- 
genus Cynips. 
The germs is here divided into six subgenera, Cynips , 
Antron , Besbicus , Philonix, Atrusca, and Acraspis, under 
each of which the systematic and biologic data are presented. 
