476 
[March 
actually the case, has a free exit from the tips of the sheaths, and that 
even if Nature secreted any poisonous fluid into the sheaths it would 
be apt to leak out from their tips, especially if the sheaths, as in most 
Inquilines, projected considerably from the “ dorsal valve.’’ It would 
seem as if the Gruest gall-flies were compelled to sponge upon the true 
G-all-flies for food and lodging for their young larvae, because Nature 
has denied them-the peculiar poison adapted to cause the growth of 
the various kinds of galls, or at all events has denied them a suitablo 
apparatus for making use of that poison. Similarly, the cuckoo-bees, 
(yNomada^ EpeMus^ Goelioxps^ &c.) lay their eggs in nests constructed 
and provisioned with pollen by pollen-collecting species, because Nature 
has denied to them the appropriate pollinigerous organs. But just as 
certain Fossorial Wasps are strictly fossorial in their habits, though 
their legs approximate in their armature to the Vespade type,* so the 
two exceptional Cynipidae mentioned above, or one of them at all events 
as we know, are strictly Psenidous in their habits, though the structure 
of the organs of oviposition in both approximates to a certain extent to 
the Inquilinous type. The whole subject is a curious one, and well 
deserves further and fuller investigation. 
It is observable that in the Guest gall-fly Auhix sj/Ivestris 0. S., con¬ 
trary to the general rule in the group A. II., the radial area is open, 
i. e. is not closed by a marginal vein. (Proc. Ent. Soc. Phila. II, p. 
37.)f In all my Cynipidae belonging to A. It. (Guest gall-flies) the 
radial area is distinctly closed, and, as I consider it, by a true vein 
which is a prolongation of the costal vein, and not a mere “ thickening 
of the margin of the wing,” as hinted by Osten Sacken. p. 36.) 
I draw this inference and the further inference that the closing of the 
radial area, though useful as a subsidiary character, is not a character 
of any high systematic value, at all events in true Fijitidm^ from the 
following facts :—I have six species of Fhjites. differing in size and in 
the sculpture and armature of the scutel and the sculpture of the head 
E. g. Miscophus, which is said by Westwood {Intr. II, p. 187) to be ^‘desti¬ 
tute of spines on the fore-legs,” but on p. 189 is said to be “very sparingly 
armed with short simple spines,” as it is figured p. 188 fig. 6, t 1. 
f I observe in specimens of this species obligingly sent me by Baron Osten 
Sacken, that in certain lights the ra'dial area seems to be closed by a brownish 
vein which is not seen on the other part of the costal edge.—March 21, 1861. 
