November 26, 1908] 



NA TURE 



1x7 



In another species the death-rate at three stages was 

 worked out, and appeared to be 50 per cent. Except in 

 one case the maximum intensity of closely similar species 

 appeared to be at different levels. 



Geological Society, November 4. — Prof. W. J. SoUas, 

 F.R.S., president, in the chair. — The relations of the 

 Nubian Sandstone and the crystalline rocks of Egypt : 

 Hugh J. L. Beadnell. The conclusions of previous 

 observers are mainly in favour of the view that the 

 granites are not intrusive into the Nubian Sandstone, but 

 that the latter was deposited round denuded masses of the 

 jjranite. The crystalline rocks south of the Oasis of 

 Kharga are first dealt with. Eight exposures of crystal- 

 line rocks were met. The sediments near the contact 

 with the crystalline rocks are generally inclined at a high 

 angle. The bedded rocks contain no fragments derived 

 from the crystalline rocks. The author concludes that 

 the Nubi.ui .Sandstone was unconformably deposited, partly 

 on preexisting sedimentary formations, and partly on the 

 planed-down surfaces of still older crystalline and meta- 

 morphic rocks. Subsequenlly it was invaded by outbursts 

 from the underlying magma, the intrusions being probably 

 connected with the elevation of the mountainous regions 

 on the cast side of the Nile. — The fossil plants of the 

 Waldershare and Fredville series of the Kent coalfield : 

 E. .A. Newell Arber. .At the boring at Shakespeare Cliff, 

 Dover, Coal-measures were reached at a depth of iioo 

 feet, and subsequently penetrated to a depth of .ibout 

 2270 feet. Thirteen seams of coal, varying in thickness 

 from I foot to 4 feet, were pierced. Coal-measures were 

 struck at 1304 feet at the boring in Waldershare Park, 

 and pierced for 1260 feet more. Five seams of coal, vary- 

 ing from I foot 4 inches to 5 feet 2 inches in thickness. 

 were struck. The boring near Fredville Park reached 

 Coal-measures at 1363 feet, pierced three seams of coal, 

 and w^as continued to a depth of 1813 feet. The speci- 

 mens of plants collected from the Waldershare and Fred- 

 ville borings were compared with plants found at Dover 

 and in other localities in Britain and abroad. The 

 in:ijoritv of species tabulated are either confined to the 

 Upper Coal-measures and the transition series below, or 

 are .Middle and Lower Coal-measure forms which are 

 known to occur in the transition series. Thus the beds 

 are the homotaxial equivalents of the Newcastle, Etruria, 

 and black-band horizons of north Staffordshire, the Ham- 

 ste.ad beds below 1233 feet in south Staffordshire, the Coed- 

 yr-allt beds and Ruabon marls of Denbighshire, the Ard- 

 wick series and beds above the Bradford four-foot coal 

 in south Lancashire, the Lower Pennant Grit of South 

 Wales, and the New Rock and Vobster series of Somer- 

 set. The majoritv of species are also common to the 

 highest zone, or the " Charbons Gras," in the Pas de 

 Calais. 



Entomological Society. November 4. — Mr. C. O. Water- 

 house, president, in the chair. — Exhibits. — W. G. 

 Sheldon : Examples of Mclitaea aurinia, var. ibcrica, 

 from Barcelona, taken last May, and examples from 

 various British and Continental localities for comparison, 

 suggesting that eventually this particular form of aurinia 

 might prove to be a distinct species. — Rare Tachinida; : 

 H. W. Andrews. A short series of Gymnosonia 

 rotundatiim, L., and a specimen of Ocyptera brassicaria, 

 F. — two uncommon Tachinids — from Glengarriff, co. Cork. 

 — Erebias from the Vosges : P. J. Barraud. A series of 

 Ercl'ia stygnc and E. ligca from the French Vosges, taken 

 in June and July this year. — Nonagria new to Britain : 

 E. P. Sharpe and A. J. Wig^htman. A series of 

 Nonagria cdelsteni, wrongly identified as N. neurica, Hb., 

 from Sussex, taken in .August this ^ear, this being 

 the first time that the species, which is quite dis- 

 tinct, had been observed. — Pseudogynes of Formica 

 rufa : H. St. J. Donisthorpe. Pseudogynes captured 

 alive at Nethy Bridge in September last, where they 

 occurred in some numbers in two nests of Formica rufa, 

 thus indicating that .Itemcles piibicollis, Eris., a beetle 

 new to Britain, is to be found in Scotland. — Rare British 

 Coleoptera : H. St. J. Donisthorpe. Examples of 

 Harpalus cuprefis, Dej., from Sandown, Isle of Wight 

 (one specimen with red legs discovered by Mr. T. Taylor 

 at .Atherslone) : Cafius cicatricosus, Er., from Snuthsea ; 



NO. 2039, VOL. 79] 



and Cryptoccphalus bipunclatus, L., taken at Niton, Isle 

 of Wight, where it was discovered by Mr. R. S. Mitford 

 last year. — A " stick " insect — apparently a new species of 

 the genus Melaxinus — bred parthenogenetically by Mr. H. 

 Main : R. Shelford. — .A long series of hybrid S. ocellaliis 

 X populi : L. \V. Newman. — Life-histories of Coleophorids 

 and hybernating Porthesia : H. J. Turner. (i) Ova, 

 larva;, and photomicrographs to illustrate the life-history 

 of Coleophora virgaureae. (2) " Nests " of the gregarious 

 hybernating larv£e of Porthesia chrysorrhoea from Waker- 

 ing marshes, Esse.x ; on several parts of the coast this 

 species has now become very abundant again. (3) Dead 

 flower-stems of Staticc limoniiim collected on November i, 

 containing the full-fed hybernating larvae of Coleophora 

 limoniella. — Rare earwig and cells of wasp: W. J. Lucas. 

 (i) .An example of Labidtira riparia. Pall, (shore earwig), 

 a large male taken near Bournemouth, August 10, and 

 kept alive since that date. (2) Two cells of the solitary 

 wasp Eumenes coarclata found in the New Forest. — Speci- 

 mens of the genera Celastrina (Cyaniris) and Everes to 

 demonstrate the racial identity of C. sikkima and C. 

 argiolus, C. jynteana and C. limbatus, E. diparodes and 

 E. argiades : Dr. T. A. Chapman. All these species 

 occur together, and appear to form a mimetic group, but 

 it would be impossible at present to determine which is 

 the model and what may be the object of the mimicry. — 

 The male and female imago, the preserved larva, and the 

 cocoon of an interesting new Lasiocampid from Durban : 

 Prof. E. B. Poulton. — Butterflies captured on a patch of 

 zinnias on the north of the Victoria Nyanza : Prof. E. B. 

 Poulton. Seventeen specimens were shown of Danais 

 chrysippus. L., of the type, and alcippus forms together 

 with the interiTiediatc examples, but no single specimen of 

 dorippus (klugii), although of three females of Hypolimnas 

 misippus, L., two were of the inaria, Cr., form mimick- 

 ing dorippus. — Specimens of Hcliconius amphitrile. Riff., 

 and H. cliarithonia, Linn., also a coloured drawing of 

 H. hermathena. Hew. : Dr. F. A. Dixey. Each of the 

 first two species showed a distinct and well-marked 

 aposeme or warning character, each of them, and especi- 

 ally the first, belonging to an extensive mimetic 

 assemblage. In the tliird species these two distinct 

 aposemes were combined. — .Aberrant forms of Polyommalus 

 bellarirus and of Zygaeiia trifolii and Z. hippocrepidis : 

 Dr. G. G. Hodgson.— The life-history of Erianthus 

 versicolor, Brunncr, an Orthopteron of the family 

 Mastacida; : J. C. Kershaw. 



Linnean Society. Nnveci.ber 5.— Dr. D. H. Scott, F.R.«., 

 president, in the chair. — Notes on some parasitic Copepoda, 

 with a description of a new species of Chondracanthus = 

 C. inflatus : Miss M. E. Balnbridge.— Some nemerteans 

 from the eastern Indian Ocean : R. C. Punnett and 

 C. F. Cooper. — Report on the echinoderms, other than 

 holothurians, collected by Mr. Stanley Gardiner in the 

 western parts of the Indian Ocean : Prof. F. Jeffrey 

 Bell. 



Mathematical Society, NV vember 12.— Prof. W. Burnside, 

 president, and subsequenlly Prof. H. M. Macdonald, vice- 

 president, in the chair. — .Address of the retiring president ; 

 Prof. W. Burnside. The address dealt with the neglect 

 of the theorv of groups of a finite order by English mathe- 

 maticians. It w-as pointed out that numerous opportunities 

 arise in comparativelv elementary teaching for emphasising 

 the importance of some of the simpler notions of the 

 theorv of groups. If such opportunities were taken a 

 student of the more advanced theory would approach it 

 with a mind already stored with concrete examples.— 

 (i) The second mean' value theorem of integral calculus; 

 (2) the representation of a function by means of a series 

 of Legendre's functions : Dr. E. W. Hobson. In the 

 second of these papers it is pointed out that a difficulty, 

 not presented in the analogous theory of Fourier's series, 

 arises in the theorv of the expansion of a function in a 

 series of Legendre''s functions, through the existence of 

 two critical points of the differential equation satisfied by 

 these functions, and an asymptotic formula for the func- 

 tions of high index, valid in the neighbourhood of the 

 critical points, is obtained. — The eliminant of three 

 quantics in two independent variables : A. L. Dixon. A 

 method is given for exhibiting the eliminant as a single 

 dc-terminant, the elements of which are formed by a rule 



