May 24, 1883] 



NA TURE 



81 



Mock Moons 



I NEVER noticed that mock moons and mock suns are not 

 always at the same altitude as the moon or sun, but I would 

 point out that when objects are high up, it is very difficult to 

 decide on their relative altitudes. If mock moons are at the 

 same altitude as the mion, then of course they are not on a great 

 circle, but on a small one, and in consequence, except when 

 they are low down, a straight line passing through the mock 

 moons will pass above the moon, and when they are high up, at 

 a considerable distance above it. In such a case, if the observer 

 does not look straight at the moon, he may ea-ily suppose that 

 one of the mock moons is higher up than the other. Is your 

 correspondent (vol. xxvii. p. 6c6) sure that they were not at the 

 same altitude on the occasion he refers to ? If, instead of facing 

 the moon and looking straight at it, he looked more at the right- 

 hand mock moon, the illusion would be produced of the left- 

 hand one appearing higher up. The same illusion is caused 

 when the horizontal lines of buildings or of a window cut the line 

 passing vertically through the moon obliquely ; so that great care 

 is required in making these observations. 



I might add that I observed the mock moons and halos on the 

 evening alluded to (April 16) from Sunderland till after 1 1 p.m., 

 and that I noticed nothing unusual in their positions or size. 

 The mock moons (or sun.) are always outside the ordinary halo 

 when their altitude is considerable. On that occasion there was 

 also visible a considerable part of the horizontal halo passing 

 through the mock moons, forming long tails to them away from 

 the moon ; also vertical and horizontal rays proceeding from 

 the moon ; forming a faint cross with the moon at its centre. 

 The horizontal rays were narrow, and reached at one time to 

 the ordinary halo, but were much fainter than the "tails" of 

 the mock moons. The vertical rays did not reach quite so far, 

 and were broad and indefinite; otherwise I suppose their cha- 

 racter (except as to brightness) w ■uld be much the same as that 

 of the "sun pillar" described by several of your recent corre- 

 spondents. T. W. Backhouse 



Sunderland, May 12 



Helix pomatia 



ALTHOUGH this species is decidedly local in this country, yet 

 it is interesting to note that the counties in which it has been 

 recorded are contiguous to one another. Its course of di-tribu- 

 tioi appears to pass through Kent, Sussex, Surrey, Hants, Wilts, 

 Glouce tershire, Berks, Oxon, Bucks, Herts, and Northampton- 

 shire, and this seems to support Mr. Stokoe in his suggestion 

 (Nature, vol. xxviii. p. 6) that it may be a geologically recent 

 importation from France (to the northern portion of which it 

 is confined in that country). 



In Murray's "Handbook to Surrey," p. 70, Helix pomatia is 

 stated to abound at Tyting Farm near Guildford, "said to have 

 been introduced from Italy " by an Earl of Arundel, and Hevan's 

 "Guide to Surrey," p. in, mentions the same locality as the 

 "habitat of the edible snail impoited from Italy," &c. I vi ited 

 this spot in September, 1880, in quest of H. pomatia, and men- 

 tioned my object to a farm labourer, who speedily produced 

 three specimens from under a log of wood, but told me that 

 they were not at all plentiful there, as the soil w as sandy and 

 not chalky, and he said I mu-tloolc for them on the neighbouring 

 chalk downs, whence his master the farmer procured his for the 

 purpo-e of adopting the diet, which, when ill, he had been 

 advised to try. Be H. pomatia indigenous or not, there is no 

 doubt its presence in England has been assited by importations, 

 for Mr. Lovell Keeve mentions its being introduced from Italy 

 by an English nobleman in the vicinity of Box Hill and Reigate 

 (cf. also Gray's "Turton," ed. 1840, p. 35). 



The Helix sealaris ieferred to in Venables' work on the Isle 

 of Wight is cited in that book as a mon-trosity of H. aspersa, 

 and Moquin Tandon's figure of the variety sealaris is of the 

 U-ual coloration of that species. The name, however, was 

 originally bestowed by Miiller on a variety of H pomatia (Lamk. 

 "An sans vert," second edition, vol. viii. p. 32), and is figured 

 as such by Draparnaud, but Venables' reference seems to apply 

 to a scalariform variety of H. aspersa observed by Dr. Gray near 

 Ventnor. W. C. Atkinson 



Streatham, S.W., May 11 



Cape Bees 



I CAN endorse all that Sir J. H. de Villiers says concerning 

 the sense of smell in the wild bees of the Cape. The aversion 



they have to sweating horses is well known, as also to the scent 

 of chopped carrots. The following instances of this have come 

 under my own notice : — 



A party of young men who had been springbok hunting all 

 the morning, off-saddled their h or- es during the hottest part of 

 the day, under the shadow of a great krantz (cliff) ; they had but 

 ju-t tied them to some trees, when the pooranimals were attacked 

 in the most vicious manner by an immense swarm of rock bees 

 from the krantz, and so dreadfully were they stung, that, 

 although the thongs that bound them were cut through as quickly 

 a> possible to enable the poor things to escape, one beautiful 

 horse was stung to death, and two more of the number were so 

 maddened that they galloped off, and for many days were quite 

 unfit for use. 



One of the Hottentot children upon our place, playing in the 

 garden near some hived wild bees, mischievously chewed up a 

 carrot, and spat it into the entrance of the hive ; the boy was 

 perfectly naked, and the next few minutes mi'/ht have been his 

 last, had not the European gardener happened to be near, and 

 hearing his shrieks-, hastened to the spot, thrust the child into a 

 newly-dug trench, and quickly covered him with earth ; but he 

 had a narrow e cape of his life, for he was literally covered with 

 stings. 



The precursor of a storm in the Karoo is generally a whirl- 

 wind of dust, and our hoys used to take advantage of the dislike 

 to storms evinced by bees, to throw up large handfuls of dust 

 into the air, when a swarm was passing overhead, when sometimes 

 the bees would be deceived and settle immediately. 



M. Carey-Hohson 



Late of Graaff Reinet, Cape of Good Hope 



The Effect of the Change of Colour in the Flowers of 

 " Pulmonaria officinalis " upon its Fertilisers 



Yesterday I had an opportunity of convincing myself by direct 

 observation that the change of colour in the flowers of Pitlmon 

 aria officinalis is of the same significance as in Jxibes aurcitm and 

 Lantana, according to Delpino and Fritz M tiller (compare 

 Nature, vol. xvii. p. 79). 



In a small locality about twenty yards long and two broad, 

 where many hundred flowers of Pulmonaria were in all stages 

 of development, its principal fertilisers were the females of 

 Anthophora pilipes, F. ; they visited almost exclusively the red 

 flowers and tho-e just beginning to change towards blue, but only 

 exceptionally blue ones. 



The first individual which I watched when it was flying from 

 fl'iwer to flower did so without any exception. Another indi- 

 vidual newly alighting on the place at first now and then visited 

 one or some few blue flowers, but the longer it continued its 

 predatory flight the more it neglected the blue flowers and 

 selected only the red ones. 



A third female of Anthophora which I followed incli-criniiu- 

 ately visited (a) red flowers of Pulmonaria, {/>) large blue flower, 

 of Glechoma, both in the following order : — (a) 16, (b) I, (a) 23, 

 (b) 1, (a) 21, (b) 62, (a) 5 flowers ; then it left the place without 

 having touched a single blue flower of Pulmonaria. 



The fourth and last female of Anthophora I followed neglected 

 completely the flowers of Glechoma; but when it visited the 

 red flowers of Pulmonaria and met for some time only with 

 already emptied ones, it became more and more disturbed 

 and hurried, and then indiscriminately visited blue and red flower? 

 until anew it found honey in a red one. J t visited (a) red and (b) 

 blue flowers of Pulmonaria in the following order : — (a) 52, {b) I, 

 (a) 18, (*) 3, (a) 16, (b) I, (a) 34, (*) 3, (a) 7, (*) 1, (a) 42, (6) 1, 

 (a) 13 ; in summa (a) 182 red, (b) 10 blue flowers. 



It is easy to be seen whether a flower of Pulmonaria when 

 visited by Anthophora contains some honey or not ; in the first 

 case the proboscis of the bee rests at least 1 to ij seconds in 

 the corolla tube, whereas in the other case it is instantly with- 

 drawn. All blue flowers of Pulmonaria which were vi-ited 

 proved thus to be empty of honey, and in all which I examined 

 with a lens in this locality the stigma was supplied with pollen. 



We may, I think, safely conclude from these observations that 

 the blue colour of older flowers of Pulmonaria, whilst increasing 

 the conspicuousne-s of the clusters of flowers, at the same time 

 indicates to such intelligent bees as Anthophora to which flow ers 

 they have to restrict their visits as well to their own as to the 

 plant's profit. Hermann Muller 



Lippstadt, May 8 



