872 
Indiana University Studies 
Among the most common cynipid productions of the eastern 
half of the United States, the agamic galls of Cynips pezo- 
machoides have always attracted considerable attention. Fur- 
nishing the type of the subgenus Acraspis, interesting because 
of the wingless females of the agamic generations of all the 
varieties, well known in the general entomological literature 
because of the experimental determination of the alternate, 
bisexual generation of variety erinacei, the species has proved 
one of the most profitable for our present studies and offers 
still other points that will undoubtedly repay further investi- 
gation. 
The hard and crystalline agamic galls of this species, altho 
matched by other species of Acraspis, are still curious muta- 
tions of plant tissues to find in the eastern United States. 
Fagan (1918:157) quotes Trimble (1892, The Tannins. Phila.) 
to the effect that the galls of variety erinacei of this species 
contain as much as 17.89% of tannic acid (to be compared 
with the 65% in the Allepo gall, Adleria gallae-tinctoriae, and 
with the 40% in our native Disholcaspis cinerosa — Trimble 
analyses) . 
The young galls of the agamic generation of Cynips pezo- 
machoides first appear in June, reaching full development in 
July and August. The insects pupate in the galls early in 
September, probably maturing soon after that, altho the adults 
do not ordinarily emerge until sometime in November or De- 
cember. With at least the northern varieties of the species, 
emergence and oviposition often occur on cold days and some- 
times when the temperature is below freezing. The agamic 
females oviposit in the buds of the white oaks. In these buds 
the inconspicuous galls of the next generation are to be found 
in the following April or May. It was as early as 1865 that 
Osten Sacken, knowing of Bassett’s early observations on sea- 
sonal alternation in Neuroterus, and believing pezomachoides 
related to the European species of Teras, predicated the alter- 
nation of generations in this species, stating (Proc. Ent. Soc. 
Phila. 4:340) : “As these wingless specimens, invariably fe- 
males, have always been reared in winter, may they not be 
dimorphous females of the winged individuals, for which we 
would have to look out, in such a case, in the early part of 
summer?” As a result of Triggerson’s work (1914), this bi- 
sexual generation has now been definitely recognized for va- 
