AUGUST 15, 1912] 
NATURE 
was the adoption at a general meeting of the 
congress of a_ resolution appointing an inter- 
national committee of entomologists to collect the 
opinions of national committees, and to bring 
themselves into relation with the existing inter- 
national committee on zoological nomenclature. 
The subject of bionomics called forth some 
interesting communications. Among these were 
Prof. Poulton’s demonstration of the remarkable 
mimetic phenomena exhibited by the forest butter- 
flies of Uganda; and Dr. R. C. L. Perkins’s series 
of colour groups in Hawaian wasps, showing the 
influence of a well-protected intruder upon the 
superficial aspect of members of the native fauna. 
The Rev. K. St. A. Rogers contributed an inter- 
esting paper on mimicry in an East African 
Lyceenid; Messrs. Donisthorpe and Crawley gave 
a good account of the founding of colonies by | 
ants; and Prof. W. M. Wheeler, of Harvard, 
criticised in a convincing manner the symbiotic 
interpretation of the association of leaf-cutting | 
ants with acacia trees in Central America. An 
ingenious explanation of the mimetic poly- 
morphism of Papilio polytes, founded on the breed- 
ing experiments of Mr. J. C. Fryer, was brought 
forward by Prof. R. C. Punnett, F.R.S., and 
evidence of the capture of butterflies by insecti- 
vorous birds formed the subject of a communica- 
tion from Mr. C. F. Swynnerton, laid before the 
section by Prof. Poulton. Some excellent photo- 
graphs from nature of butterflies in their resting 
attitudes were shown by Mr. A. H. Hamm, of 
the Hope Department. 
Space will not allow of more than a _ bare 
mention of the sectional proceedings in the 
sections of morphology, systematics, and dis- 
tribution, but among many papers of high interest 
may be specially enumerated those of Prof. H. J. 
Kolbe (Berlin) on the zoogeographical elements 
of continents; Prof. G. H. Carpenter (Dublin) on 
the Maxillule in beetle larve; Dr. G. Horvath 
(Budapest), Padre L. Navas (Barcelona), and Dr. 
F. A. Dixey (Oxford) on features in the wings 
of insects; of Dr. T. A. Chapman (Reigate) on 
regeneration in L. dispar; of Baron K. von Rosen 
(Munich) on fossil Termites; of Dr. 
(Labes) on geographical distribution and varia- 
tion in certain insects; of Dr. P. Calvert (Phila- 
delphia) on the Odonata ; and of Mr. R. S. Bagnall 
(Oxford) on the T hysanoptera. 
Among the papers read before general meet- 
ings were two of exceptional interest. One of 
these, by Dr. Adalbert Seitz, of Darmstadt, em- 
bodied the results of some experiments on insect 
vision, giving much evidence of the large part 
played by the sense of sight in the mutual recog- 
nition between the sexes. The other, by Prof. 
V. L. Kellogg, of Stanford University, U.S.A., 
brought forward some striking facts as to the 
distribution of the species of Mallophaga, many 
of these, according to the author, having become 
associated with their present hosts before the 
differentiation of the latter into separate species. 
Among other noteworthy communications made 
in general meetings of the entire congress were 
NO. 2233, VOL. 89] 
P. Speiser | 
Crt 
papers by Rey. G. W heeler (Leadon) and Mr. 
G. T. Bethune-Baker (Birmingham) on nomen- 
clature; by Prof. J. H. Comstock (Ithaca, U.S.A.) 
on the silk of spiders; Prof. J. Van Bemmelen 
(Gréningen) on the development of the butterfly 
wing; Mr. J. W. Taylor on distribution; Mr. L. 
Doncaster (Cambridge) on sex-limited inheritance ; 
Dr. Handlirsch (Vienna) on distribution; and Mr. 
S. A. Neave on his travels in East and Central 
Africa. 
An exhibition of Acrine butterflies was speci- 
ally arranged by Mr. H. Eltringham, to whose 
exertions as one of the local secretaries the success 
of the congress is largely due; and of Pierine 
butterflies by Dr. F. A. Dixey. The members 
of the congress were hospitably entertained on 
August 7 at Nuneham by the Rt. Hon. L. V. 
Harcourt, M.P., Secretary of State for the 
Colonies, and by John’s College at Bagley 
Wood. On August 9 they met, to the number 
of nearly 150, at a banquet in the hall of Wad- 
ham College; and on August 10 they were re- 
ceived by the Hon. W. Rothschild, F.R.S., at 
Tring, spending there a most enjoyable and profit- 
able day. The next congress will be held at 
Vienna in 1915, under the presidency of Prof. 
Anton Handlirsch. 
ARTIFICIAL DAYLIGHT. 
NUMBER of researches has recently been 
made on the imitation of daylight by arti- 
ficial means. There are many industries, such as 
dyeing, carpet manufacture, coloured silk, &c., to 
which an artificial illuminant which resembled 
normal daylight exactly would be very serviceable. 
In some cases, where very fine discrimination be- 
tween delicate shades of colour is necessary, the 
work is practically brought to a standstill as soon 
as artificial light has to be used. In the same way 
a standard artificial daylight would be of consider- 
able value to florists, drapers, &c., and might en- 
able artists to work in the evening with the same 
facility as by day. 
Practically all the present illuminants differ con- 
siderably from daylight in colour, usually having 
an excess of red and a deficiency in blue. Mr. 
T. E. Ritchie, in a recent paper before the Ilumina- 
ting Engineering Society in London,! contended 
that the inverted arc gave the closest approxima- 
tion, being apparently preferable to ordinary direct 
are lighting. The reason for this seems to lie in 
the fact that reflection from a diffusing white ceil- 
ing tends to suppress the excess of blue-violet. 
In the United States the Moore vapour tube, in 
which carbon dioxide is subjected to a high fanoce 
electric discharge, is said to give a white light 
almost identical with daylight, and, indeed, to be 
more constant than climatic variations allow day- 
light to be. The carbon dioxide Moore tube seems 
to have been largely used in silk mills and else- 
where in the United States, but it requires an 
alternating current and a special form of in- 
l [Uuminating Engineer (London), February, :912. 
