96 NATTJBAL HISTORY SOCIETY OF DUBLIN. 



FRIDAY, MAECH 4, 1864. 

 Robeet Callwell, Esq., M. E. I. A., V. P., in the Chair. 



Mr. Archer, Honorary Secretary, read the Minutes of the last meet- 

 ing, which were confirmed. 



The following paper was then read : — 



On Ieish Yespid.33. By Richabd L. Edgewoeth. 



The following paper on the Irish Vespidae I wrote at Dr. Perceval 

 "Wright's request, intending that it should appear in the "Annals of Na- 

 tural History ;" but, being asked to contribute a paper to this Society, I 

 thought it advisable to add my mite to the interest of our meetings, and 

 at once accorded to the wishes of your Secretary. 



The subject which I have the honour to bring before the notice of 

 the Society this evening is one of peculiar interest, both because we 

 possess no memoir of the Irish Vespidae, and because the internal 

 economy of the Vespidae, 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 (Linn.), Vespa 

 Germanica (Eabr.), Vespa rufa (Linn.), and two tree Wasps, the. Vespa 

 Britannica (Leach), and Vespa holsatica (Fabr.), (=F. Sylvestris, Scop.). 

 The Vespa borealis — a species originally discovered by Mr. Smith — 

 —and the Vespa Crabro (Linn.), 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 commu- 

 nity, originally made by Reaumur, and since repeated by many natu- 

 ralists. Reaumur assumed that there were 10,000 cells, and that each 

 and all produced during the season three Wasps, thus producing 30,000 

 Wasps. That Reaumur's calculation is erroneous is proved by the fact 

 that 30,000 Wasps could not be contained in any average nest. Eor, 

 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 ; therefore, 30,000 

 Wasps will almost occupy the entire contents of a sphere whose diame- 

 ter is ten inches. Now, a nest of such dimensions as this is- seldom to 

 be met with in these countries. I have therefore shown that the 

 30,000 Wasps which Reaumur postulates would occupy the solid con- 

 tents of the largest known nest ; but two-thirds of each nest is occupied 

 with cells ; therefore in a nest of ten 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 

 his own space ; therefore, even a nest of ten inches in diameter could not 

 contain more than 3000 Wasps. 



