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22:1-198) are the bases of our knowledge of alternation of 
generations among the gall wasps. Such studies as Fockeu’s 
(1889, Hist. Galles) and several others in gall histology are 
superior to the work we have done in America. Beyerinck 
(1883) and Paszlavzsky (1882-1883) studied the early devel- 
opment, or what might be called the embryology of the gall 
structure, an aspect of our problem which has hardly yet been 
considered in America. 
If the present review of European Cynips serves to clear 
the way for further work on the group, or if it serves to 
awaken interest in a reconsideration of the Central European 
fauna in the light of the more northern and the more south- 
ern faunas, and even of the related American subgenera, then 
this part of our study shall have accomplished its purpose. 
Cynips (Cynips) folii Linnaeus 
agamic and bisexual forms 
AGAMIC FEMALE. — The entire insect rich rufous and piceous 
(Mediterranean and Central Europe) to entirely black (more northern 
Europe) ; the head distinctly narrower than the rather robust thorax 
(Mediterranean and Central Europe) or practically no narrower 
(more northern Europe) ; the mesonotum largely punctate and hairy 
(Mediterranean and Central Europe) or largely smooth and naked (more 
northern Europe); the abdomen not more than twice again as long as 
high, the tip of the second segment approaching the tip of the abdomen 
dorsally; the tip of the second abscissa of the radius not bent, with or 
without a distinctly triangulate enlargement; length 2.1 to 4.4 mm. in 
three varieties. 
The central European variety folii (q.v.) is nearly identical with 
C. longiventris longiventris and close to the other varieties of Cynips 
in the same region; the more northern variety atrifolii is very near 
C. longiventris forsiusi and C. divisa atridivisa of that region. 
BISEXUAL FEMALE AND MALE.— As described for the genus 
and subgenus (q.v.). Very similar to the bisexual forms known for 
other species of European Cynips. Differing in having the legs a 
brighter, clearer yellow and the mesonotum and mesopleuron entirely 
smooth and shining. 
AGAMIC GALL. — Rather large, spherical, filled with soft and spongy 
fibers. Up to 30. mm. in diameter. Externally smooth and naked, or 
set with small, irregular papillae; fresh specimens green, yellowish, or 
red in color, becoming yellowish brown or russet brown on drying; the 
outer shell rather thin, readily distinguished from the spongy interior 
of the gall; this spongy material filling all the gall, but consisting large- 
