458 
[March 
bably have been caused by their having been put in a glass jar instead 
of in paper; for they were quite green when gathered and moulded 
considerably in spite of all my care. Thus the question still remains 
to be settled, whether inaniH^ as well as spongifica^ has an autumnal 
dimorphous form. I strongly suspect that it has. It is possible, however, 
that it has not, and it is possible that it may have an autumnal dimor¬ 
phous form entirely distinct from aciculata. Similarly the S S and 
9 9 of Formica apMdicola Walsh, and F. latipes Walsh, are scarcely 
or not at all distinguishable, while the 9 9 are as different as two species 
of the same genus can well be. In either of the above two cases it will 
be necessary to consider O. q. inanis as a distinct species, and I there¬ 
fore consider it provisionally as distinct; though I am inclined to be¬ 
lieve that it is merely a distinct race of C. q. ^pongifica^ which has 
acquired a permanent habit of attacking the red-oak exclusively instead 
of the black-oak, just as I have shown that there is a distinct race of 
Glgtus pictus Drury, which has acquired a permanent habit of attack¬ 
ing the locust exclusively instead of the hickory. (See my Paper Proc. 
Bost. 8oc. Nat. Hist., Feb. 1864.) 
I infer that the form inanis does not sometimes attack the red-oak 
producing inanis galls, and sometimes the black-oak producing spon- 
gifica galls, from the following fact:—The red-oak near Rock Island 
grows exclusively upon high bluffy land, where it is intermixed pro¬ 
miscuously with black-oak. But although the gall of G. q. inanis is toler¬ 
ably abundant there on the red-oak, I never saw but a single gall of spon~ 
gifica (which it will be remembered attacks the black-oak) on the bluffs, 
nor any anywhere within half a mile of the spot where my inanis galls 
were all gathered, nor within half a mile of any spot where I ever found 
the gall inanis. On the other hand on the flat sandy bottom land, 
where the galls of spongifica occur in profusion, there are no red-oaks, 
so that the Converse of the above question, viz., whether the form spon¬ 
gifica sometimes attacks the black-oak producing spongifica galls and 
sometimes the red-oak producing inanis galls, cannot be tested. 
The galls of inanis and spongifica, although at first sight essentially 
distinct, are constructed upon the same fundamental principle, viz., a 
central nucleus, in which the larva lies, connected with a more or less 
thin and irregularly spherical shell by radiating filaments. The only 
differences are, that the gall of inanis ranges from | to Ig- inch, and 
