1864 .] 
479 
antennae is, in the smaller species of these insects, sometimes exceed¬ 
ingly difficult to count. It would be easy to mention a dozen cases 
where authors have erred in counting them, and subsequently corrected 
their own errors; and frequently two different authors disagree as to 
the number of antennal joints in the same species. Dahlbom, for ex¬ 
ample, says that Ibah'a cultellator Latr., has the h antennae 14-jointed, 
and Westwood says that they are 15-jointed and figures them as 15- 
jojnted ! (See Brulle Hyme.nopt. IV, p. 636, Westw. Intr. II, p. 121, 
fig. 17 and p. 126.) I have myself frequent occasion in this Paper to 
differ from other writers on this subject, and can only say that if I err 
in so doing it has not been for the want of pains-taking. As in many 
species there is a long terminal joint in the 9 antenna^ with or without 
a medial connate joint or obsolete suture, and as this false suture has 
sometimes been inadvertently taken for a true one, I have stated in 
each description the proportional length of the last joint, and whether 
it has a false suture or not. In reality a 13-jointed 9 antenna with a 
long 13th joint, with or without a medial connate suture, is evidently 
the equivalent of a 14-jointed 9 antennae with the two last joints short. 
On the whole, in the present state of science, generic determinations 
of Cynipidae must necessarily be provisional, and I have therefore in 
each case merely attempted to approximate to accuracy, and to supply 
the deficiency by careful statements of such characters as appear to be 
of generic value. Taking Synophrus (.^) Iseviventris 0. S., Amblyno- 
tus (f) petiolicola 0. S., and Synerges (f) oneratus Harris, as types 
of three inquilinous genera called provisionally Synophrus, Amhlyno- 
fus and Synerges^ I find the following generic distinctions to be common 
to the different species which I have arranged under those generic 
names. 
Synophrus. Antenn® 15-jointed, 9 Id-jointed, or 13-jointed with the last 
joint long. Thorax glabrous under the lens before theseu^el; scutel rugose. 
Pleura of thorax with a large spot under the wings, which is glabrous and as 
highly polished as the abdomen. Abdominal peduncle rather indistinct, simple 
and truncate-conical, the large end of the cone towards the 2nd abdominal 
joint. Second abdominal joint occupying nearly or quite the entire abdomen, 
exclusive of the peduncle. 
Amhlynotus. Antennae 15-jointed, 9 12-jointed, the last joint full twice as 
long as the penultimate. The other characters the same as Synophrus, except 
that what appears at first sight to be the second abdominal joint is divided by 
a very faint connate suture into two joints, which are dorsally subequal %, but 
