o4 THE ENTOMOLOGIST. 
produced by Aphilothrix Sieboldii, without perceiving their 
very close correspondence with the small aborted acorns we 
find so commonly on the long peduncles of Quercus pedun- 
culatata. On these peduncles it is not unusual to find one 
normally developed acorn near the base, and one, two, or 
three aborted acorns beyond it, as though the first had 
appropriated the sap destined for the nutriment of the others, 
as well as its own. These aborted acorns are manifestly 
represented by the galls in question, the stigma in both 
instances being the only part of the acorn that protrudes 
beyond the cup.—Edward Newman. 
The Synergi—or fellow-workers, or inquilines, or lodgers 
—have been lately mentioned in the ‘ Entomologist, and a 
short abstract of Dr. Mayr’s treatise on them may be of use 
to the observers of galls. He praises Hartig’s work as being 
a good foundation for the history of oak-gall-making flies, 
but observes that the above author is less successful with 
regard to the Synergi, which failure, he says, may be owing 
to the great difficulty in determining the often very variable 
species. He adds that these difficulties can only be over- 
come by continual researches, and by complete and plentiful 
materials brought together and well arranged. He next says 
that he has particularly studied the lodgers for a series of ~ 
years, and mentions his examination of Hartig’s type speci- 
mens, and the help he has received from correspondents, and 
the division by Foerster of Hartig’s genus Synergus into two 
genera, Synergus and Sapholytus, and notices the characters 
of these two genera, and also of Ceroptre, Phanacis, Peri- 
clistus, and Xenophanes. The genus Ceroptre, he says, is 
interesting on account of its biology. He has reared from 
C. arator, Hart., more than six hundred females, but not one 
male; and of C. Cerri, Mayr, ninety-eight females, and only 
four males, and he supposes that only some few females are 
impregnated, but that the unfertilized also lay developing 
eggs. He then defines two kinds of parthenogenesis: the 
mixed parthenogenesis, of which C. Cerri is an example; 
and the Thelykotik, or simple female parthenogenesis, repre- 
sented by C. Arator. He next returns to the difficulty of 
ascertaining the species of Synergus, owing to their great 
variableness, of which S. melanopus, that lives in many 
kinds of galls, is the chief example, and concludes that most 
