426 



NATURE 



\Sept. 24, 1874 



they differ Iruin one aiujlhei' in llieir dcijrees of inicUiguncc ; 

 and his observations, though of course not conclusive, are in- 

 teresting and suggestive. 



If again we examine the hind legs of bees, we shall find 

 similar gradations. In Prosopis (Fig. 32) they do not differ 

 materially from those of genera which supply their young with 

 anim.al food. Portions of the leg, indeed, bear stiff hairs, the 

 original use of which probably was to clean this burrowing insect 

 from particles of sand and earth, but which in Prosopis assist also 

 in tlie collection of pollen. 



Fig. 33 represents the hind leg of Sphecodes (Fig. 34), a 

 genus in which the tongue resembles in form that of Ilalictus. 

 Here we seethe hairs decidedly more developed, a modification 

 which has advanced still further in Halictus (Fig^ 35), in which 

 we see that the development of the hairs is most mai ked on those 

 segments of the hind legs which are most conveniently situated 

 for the collection and transjiort of pollen. 



In Panurgus the same change is still more marked, and 

 the pollen-bearing apparatus is confined to the titi \z.rA 

 first segment of the tarsus, a differentiation which is even 

 more apparent in Anthophora. In these bees the pollen is 

 simply entangled in the hairs of the leg as in a brush, but 

 there are other genera, as for instance the humble bees and the 

 hive bee, which moisten the pollen with honey, and thus form it 

 into a sticky mass, wliich is much more easy to carry, anil is 

 borne, not round the leg, but on one side of it. In the humble 

 bee (Bombus, Fig. 36), for instance, the honey is borne on the 

 outer side of the hinder tibia;, which are flattened, smoothed, 

 and bordered by a row of stiff curved hairs, which thus constitute 

 it a' sort of little basket. Lastly, in the hive bee (Fig. 37), the 

 adaptation is still more complete, the hairs on the first tarsal seg- 

 ment are no longer scattered, but are arranged in regrdar rows ; 

 and the tibial spurs inherited by Bombus from far-distant 

 ancestors have entirely disappeared. 



In some bees the pollen is collected on the body, and here also 

 we find a remarkable gradation from Prosopis, which has only 

 minute and simple hairs, like a wasp ; through Sphecodes, a 

 Nomada, in which the longer hairs are still few, and generally 

 simple, though some few are feathered ; to AnJrena and Halictus, 

 where the hairs are much more developed ; a change which is 

 more marked in Sarapoda, CoUetes, and Megachile ; still more 

 so in Osmia and^ Anthophora ; until we come to the humble bees, 

 in which the whole body is covered with long feathered hairs. 



Although llowers present us with all these beautiful and com- 

 plex contrivances, whereby the transfer of pollen from llower to 

 flower is provided for and waste is prevented, yet they are imper- 

 fect, or at least not yet perfect, in their adaptations. Many small 

 insects obtain access to llowers and rob them of their contents. 

 Malva rotiindifv/ia can be, and often is, sucked by bees from the 

 outside, in which case the flower derives no advantage from the 

 visit of the insect. In Mcd'uago saliva, also, insects can suck 

 the honey without effecting fertilisation, and the same flower 

 continues to secrete honey after fertilisation has taken place, and 

 when apparently it can no longer be of any use. Fritz Midler 

 has obser^'ed that, though Posoijiit-na fnigrans is exclusively 

 fertilised by night-flying insects, many of the flowers open in the 

 day, and consequently remain sterile. 



It is of course possible that these cases may be explained 

 away ; nevertheless, as both insects and flowers are continually 

 altering in their structure and in their geographical distribution, 

 we should necessarily expect to find such instances. Animals 

 and plants constantly tend lo adapt themselves to their condi- 

 tions, just as water tends to find its own level. 



I have been good-humouredly accused of attacking the little 

 busy bee, because I have attempted to show that it does not pos- 

 sess all the high qualities which have been popul.arly and poeti- 

 cally ascribed to it. But if scientific observalious do not alto- 

 gether support this intellectual eminence, which has been as- 

 cribed to bees, they have made known to us in the economy of 

 the hive many curious peculiarities which no poet had ever 

 dreamt of, and have shown that bees and other insects have an 

 importance as regards flowers which had been previously unsus- 

 pected. To them we owe the beauties of our gardens, the 

 sweetness of our fields. To them flowers .are indebted for their 

 scent and colour, nay, their very existence in its present form. 

 Not only have the brilliant colours, the sweet scent, and the 

 honey of flowers been gradually developed by the unconscious 

 selection of insects, but the very arrangement of the colours ; 

 the circular bands and railiating lines, the form, size, and posi- 

 tion of the petals, the arrangement of the stamens and pistil, arc 

 all arranged with reference to the visits of insects, and in such a 



manner as to ensure the grand cbject \\liich renders these visits 

 necessary. 



Thus, then, I have attempted to point out some of the rela- 

 tions which exist between insects and our common wild flowers ; 

 the whole subject is one, however, which will repay most careful 

 attention, for, as Muller has truly said, there is no single species 

 the whole history of which is yet by any means thoroughly 

 known to us, and while, with reference to the regions of thought 

 brought before us by the president on Wednesday evening, few 

 can hope themselves to assist in the progress of truth, the case 

 is very different with reference to my subject of this evening, in 

 which every one of us by care and perseverance may fairly hope 

 to add something to the sum of human knowledge. 



NOTES 



We hear that it is most probable that Dr. T. Lauder Brunton, 

 F.R. S. , whose iuves'igntions in the science of therapeutics h.ave 

 made him so well known to physiologists and pathologists gene- 

 rally. Mill undertake the editorship of the rractitioiier, rendered 

 vacant by the death of Dr. Anslie. 



The forty-seventh congress of German naturalists and physi- 

 cists opened at Breslau on Sept. iS. The proceedings were 

 opened by the eminent chemist. Prof. Loewig, who expressed 

 his satisfaction at seeing so many foreigners, whose presence in 

 that assembly, he added, was a living testimony to the truth that 

 science was of no country. Capt. von Dechen read a paper 

 upon the present state and the future prospects of geology. 

 After him, Prof. Virchow, of Berlin, spoke upon miracles re- 

 garded from the scientific standpoint. The several sections were 

 then constituted, and the members of the congress afterwards 

 adjourned to a banquet. In the evening an open-air entertain- 

 ment was given by the city, and a telegraphic greeting was sent 

 to the Emperor. 



The fortieth congress of the French Institute of the Provinces, 

 Les Mondcs informs us, opened at Rodez on Monday last, under 

 the presidency of M. de Toulouse-Lautrec, and will last ten days. 

 There are five sections, in which questionsare discussed connected 

 with the mathematical, physical, and natural sciences, agricul- 

 ture, industry and commerce, anthropology and the medical 

 sciences, history and archeology, philosophy, literature, the fine 

 arts, and social economy. This is certainly comprehensive 

 enough. 



Tme last expedition for observing the transit of Venus is now 

 on the point of leaving England for Egypt. It has developed 

 into one of considerably greater magnitude than was at first in- 

 tended. The Government expedition organised by Sir George 

 Airy, instead of being located at Alexandria, will have its head- 

 quarters at Cairo, the longitude of which city is to be found by 

 exchange of telegr.aph signals with Greenwich, for which purpose 

 a branch station will be established for a time at yVlex.T.ndria: 

 For the actual observation of the transit, Caiio, Thebes, and Suez 

 are selected, the longitude of the last two being obtained by ex- 

 changing telegraph signals with Cairo. The photographic branch 

 of the enterprise will probably be at Thebes. Private expeditions 

 have been organised, all of them in concert with the ICnglish 

 Government one. The whole may be enumerated as follows : — 

 English Government Expedition. — Chief captain, C. Orde 

 Browne ;"] i>hotogiaphic branch, Capt. Abney ; astronomers, 

 Mr. S. Hunter and Mr. Newton. Prof. Dijllen, the Russian 

 astronomer, and Col. Campbell have organised private expedi- 

 tions to Thebes. IJr. Anvers 'proposes to be either at Cairo or 

 Thebes, and Admiral Ommanney may also join the English party 

 as an associate astronomer. Tlie whole of the telescopes and 

 huts from Greenwich are now on board the Peninsular and 

 Oriental vessel HiiiJostait, which is to leave Southampton on- 

 the 1st proximo, , _^ 



