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466 Prof. R. L. Edgeworth on Irish Vespide. 
XLIII.—Notes on Irish Vespide. By Ricnuarp Lestock 
EpcewortH, of Trinity College, Dublin*. 
Tue subject which I have the honour of bringing before the — 
notice of the Dublin Natural History Society this evening is — 
one of peculiar interest—both because we possess no memoir 
on the Irish Vespide, and because the internal ceconomy of the 
Vespida, as of all the higher Hymenoptera, cannot but command ~ 
our unqualified admiration. Of the seven species of British 
wasps described by Mr. Smith we possess only five :—three 
ground-wasps—the Vespa vulgaris, V. Germanica, V. rufa; and 
two tree-wasps—the V. Britannica and V. holsatica or sylvestris. 
The Vespa borealis (a species originally discovered by Mr. Smith) 
and the V. Crabro, as far as I am aware, have not been yet 
noticed in Ireland. 
Before I proceed to the consideration of the details of each 
species, it is necessary to allude to the estimate of wasps in a | 
populous community, originally made by Réaumur, and since ~ 
repeated by many naturalists. Réaumur assumed that there — 
were 10,000 cells, and that each cell produced during the sea- 
son three wasps, thus producing 80,000 wasps. That Réaumur’s — 
calculation is erroneous is proved by the fact that 30,000 wasps — 
could not be contained in any average nest. For, assuming, 
according to Mr. Smith, that each wasp is in length seven lines, — 
and in depth and breadth respectively two lines, the space which — 
each wasp must occupy will be 0:0162 of a cubic inch; there- — 
fore 30,000 wasps will almost occupy the entire contents of a _ 
sphere whose diameter is 10 inches. Nowa nest of such di- © 
mensions as this is seldom to be met with in these countries. I 
have therefore shown that the 30,000 wasps which Réaumur — 
postulates would occupy the solid contents of the largest known — 
nest. But two-thirds of each nest is occupied with cells; there- — 
fore in a nest of 10 inches in diameter there could not be more — 
than 10,000 wasps in the closest possible juxtaposition. Now 
it is reasonable to suppose that each wasp requires at least three 
times its own space; therefore even a nest of 10 inches in dia- 
meter could not contain more than 3000 wasps. 4 
Again, I shall show that those phenomena are not presented 
which we should expect from the presence of 30,000 wasps. 
I find by observation that each wasp occupies about twenty — 
minutes in each journey, and remains about twenty minutes in — 
the nest after he has come in, and therefore each wasp passes — 
the entrance of the nest three times an hour; therefore the 
number of wasps in-a nest is a third of the sum of exits and en- — 
* Communicated by E. Perceval Wright, M.D., F.L.S., Professor of | 
Zoology, University of Dublin. 7 
