510 



NA TURE 



\_Scpt. 30, 1880 



beetle reared from a parthenogenetic ovum. With your per- 

 mission I shall now endeavour as briefly as possible to give those 

 circumstantial details without which a bald statement of results 

 would not carry with it a rational conviction of the accuracy of 

 my observations. 



From beetles gathered in the beginning of last April I had a 

 batch of eggs on the 7th, which hatched out on the 21st of the 

 same month, and on May 13-15 yielded about thirty pup^, 

 which were immediately put into heparate vessels. On the 20th- 

 22nJ appeared the imagines, of which ten subsequently turned 

 out to be females, and were placed together in pots, but not before 

 the greatly enlarged abdomen had given unmistakable evidence 

 of their sex. The first eggs, three batches, were laid on June 2 

 (so completing the cycle, from egg to egg, in fifty-six days). On 

 the 1 2th of the month I found in one of these batches, consist- 

 ing of forty-two eggs, thirteen developed, of which two hatched 

 out, the larvje dying shortly afterwards. Others seemed to have 

 partly hatched, but most eventually perished in the shell. At 

 this time fertilised eggs were hatching in nine days. It appeared 

 to me that several of the thirte.en were imperfectly or monstrously 

 developed ; one, for example, having only one misshapen (?) 

 mandible ; another, excess in number and irregularity in group- 

 ing of the eye-spots ; &c., &c. Again, on June 17 I found in a 

 parcel of (twenty-five) eggs, laid June 6-7, six which had deve- 

 loped up to the hatching. In the usual course, at the time of 

 hatching, the young larva comes out of the shell clear like 

 barley-sugar, but blackens afterwards ; in the case of these par- 

 thenogenetic larvK which do not hatch out, tliis blackening takes 

 place within the shell. In a third batch, of over twenty eg^'s, 

 laid June 8, I found three eggs similarly developed. In the 

 meantime, and afterwards, many dozen batches had been laid, 

 in which, however, I did not detect any development. 



A second experiment miscarried; but I was more succe sful 

 with a third and fourth. From a batch of eggs laid June 5-6 

 I derived pupfc which on July S following I placed separately in 

 pots, and obtained from "them thirteen beetles, of which seven 

 turned out to be females. About the same time I brought in 

 from the fields some well-grown larva;, the beetles from which 

 were isolated immediately after their exclu-ion, and subsequently 

 yielded eight females. These (seven and eight) were all kcjit in 

 separate pots during the course of the experiment. Of the seven 

 no less than five laid eggs which afterwards developed parth;no- 

 genetically. They laid as many as ten parthenogenetic batches 

 among them, but while some of them laid three such batches, 

 others laid only one. These were invariably the first batches 

 laid, and none of the batches laid subsequently contained any 

 viable eggs while the experiment lasted, whicliwas in some cases 

 up to the tenth batch. Of the eight beetles of the fourth group, 

 only one laid one parthenogenetic egg in its first batch. The 

 mimber of parthenogenetic eggs in a batch varied from one to 

 seven. In four batches there was only one such egg; in three 

 batches five, and in the other four batches two, three, six, and 

 seven respectively. The total eggs in a batch averaged 417, 

 and as there were thirty-six parthenogenetic, the proportion over 

 all was I in 1 2 J. Hov\ever, as may be supposed, the proportion 

 in the individual batches varied very much, one small parcel of 

 only eleven eggs having as many as five developed. 



In most of thc-ie cases also the larvae perished in the shell. A 

 few hatched out more or less completely, and died. Two, how- 

 ever (of the seven in one batch), were more fortunate. These 

 came out on July 29, and for some hours seemed very feeble and 

 barely alive. Next morning I found that one, which subse- 

 quently took the lead of its fellow in all respects, had crawled 

 away under cover, and the other was soon able to follow its 

 example. I could not find that they had eaten anything till the 

 evening of the 31st. After that, however, they throve apace. 

 The larger one passed its first and second moults on the 3rd and 

 7th of August, the smaller following it on the 4th and 8th. The 

 former pupated on the 14th, and the imago was excluded on the 

 19th. The latter, having pupated, August 15-16, appeared to 

 go on well till the time for the excluiion of the beetle, when its 

 further development became arrested, and it died. The survivor 

 was weakly at first, and rather imperfect always as regards the 

 elytra, which are somewhat small, and do not close in the middle 

 line. It has, however, thriven well, and developed that enlarge- 

 ment of the abdomen peculiar to the female. But up to the 

 present (September 22) it has laid no eggs, nor shown any incli- 

 nation towards males placed in the pot with it. 



When it became obvious that no more parthenogenetic eggs 

 were to be obtained from these lieetles, I placed the survivors of 

 them in succession in a pot with a (the same) male beetle, with 



the result that most afterwards laid fruitful eggs in the ordinary 

 way. I mention this because it seems to be in contradiction, as 

 far as these insects are concerned, with the statement of von 

 Siebold (" Beitriige," p. 89) : "Es ist nun eine bekannte Sache, 

 dass, wenn Insecten-WeilDchen vor der Begattung erst einmal 

 Eier zu legen angefangen haben, ihre Mannchen alsdann mit 

 ihren verspateten Liebesbezeigungea bei ihnen nichts mehr 

 auszurichten im Stande sind." 



If now I may be permitted to make a few general observa- 

 tions on some of the points indicated for further inquiry, rather 

 than established, by the foregoing experiments, I would say: 

 (i) that parthenogenesis seems to occyr chit (ly in the first-laid 

 batches ; (2) that it is peculiar to some females, while others 

 appear to be exempt from it; (3) that confinement and domesti- 

 cation, as it were, acting hereditarily, which we already know 

 so profoundly to affect the generative system in the higher 

 animals, appear to favour this mode of reproduction in Gastro- 

 physa raphani ; (4) that there are degrees of viability in parthe- 

 nogenetic embryos, so that the development seems to be arrested 

 chiefly at certain points, as at the hatching of the egg and the 

 exclusion of the imago. In this respect the Gastrophysa egg 

 behaves very much as the ovum of Botiibyx mori is reported to 

 do (f. "Beitriige," pp. 230-232). (5) Another point in which 

 G. raphani agrees- with other parthenogetically reproductive 

 arthropods is its many-broodedness in a season. There may be 

 three or four generations in direct succession in the year, and 

 there is a constant succession of eggs all the time. In this 

 it appears to differ from any of its allies with which I am ac- 

 quainted. (6) I in.ally, the case of G. raphani would seem to be 

 one of true parthenogenesis in its most restricted sense — the 

 same beetle which in the unimpregnated state lays sterile eggs, 

 with here and there one capable of development, after receiving 

 the male element, laying eggs which are fertile and develop in 

 the ordinary way. That is to say, the ova are true ova, and not 

 pseud-ova or buds, the parent a perfect female and not an 

 " Amme" like the summer Aphis. J. A. Osborne 



Milford, Letterkenny, Ireland, September 22 



Observations of Auroras on August 12 and 13 

 The finest display was between 10 and II o'clock on the 

 evening of the 12th, when a magnificent corona was formed 

 almost exactly on yCygni. At this time the bases of the columns 

 on the eastern horizon were di^tinctly red. Unfortunately the 

 spectroscope could not be brought to bear until the aurora had 

 faded to a small fraction of its greatest brightness. With a 

 very small dispersion (Vogel spectroscope) the spectrum was 

 continuous from W.L. 557 mm. to W.L. 473, with strong traces 

 of a finely banded spectrum, terminating abruptly at the great 

 line 557. Towards the violet an isolated line was seen and 

 measured. 



On the 13th the great line was seen and ahso traces of the 

 others. The measures may be summarised as follows : — 



Wave-length. Spectroscope. No. of measures. 

 557-16 ± 0'20 Grubb 8 



527-5 .. I 



(469-6 ,, I 



( 473'2 Vogel I 



J 430 Grubb ... In middle of field 



(434 Vogel I 



The Grubb spectroscope has a dispersion of 5° 40' from C to //. 

 The first line was measured with an illuminated micrometer wire, 

 the others with the edge of an opaque screen. The Vogel spec- 

 troicope has a scale of bright lines with sixty divisions to the 

 whole visible spectrum. Ralph CorELAND 



Lord Lindsay's Observatory, Dunecht 



Ice at High Temperatures 



From Mr. Hannay's letter (Nature, vol. xxii. p. 4S3) and 

 from private communications I have received it appears there 

 has been a little misc->nc"p'i-) 1 as to the manner in which I 

 judged of the temperature oi t!ie ice in the experiment referred 

 to in Nature, ibid., 435. Mr. Hannay's theory, that the ice 

 was protected from the hot glass by an intervening layer of 

 vapour, at first occurred to myself and to others as the true 

 explanation of the phenomenon, but that this explanation will 

 not serve in the present case is, I think, proved by tlie fact that 

 a thermometer was imbedded in the ice and rose to temperatures 

 varying in different experiments between 120° and 180° C, at 



