THE MEDITERRANEAN NATURALIST 
91 
quito and the house-fly, Mrs. C. B. Aaron brings 
forward some very serious indictments against 
these household pests. 
Not only do they assist materially in the dis- 
semination of Bacteria, and thus serve as efficient 
propagators of infectious diseases, but she also 
adds that they act as carriers of such parasites as 
Filaria, and some species of Toenia. For their 
extermination she suggests several mechanical and 
easily applied methods, among which may be 
noted, the free use of crude petroleum in all 
damp places, and in all collections of stagnant 
waters. 
The oils floats on the surface and when the larvse 
come to the surface to breathe, the oil clogs the 
breathing tubes and thus suffocates them. 
Other methods are discussed such as the rearing 
of the dragon-fly which is a natural enemy of the 
mosquito; but this is not recommended owing to 
the trouble and uncertainly that are entailed. 
In the museum of postage stamps at Vienna, 
says the “Nuova Autologin”, there is a collection 
of 100,000 examples; among the rarest and most 
valuable of which are the stamps that were used 
on the dispatches that were sent during the Fran- 
co-Prussian war of 1870-1871. 
A statistical table, showing the comparative fre- 
quency of storms and of lightning in various parts 
of the world, has been drawn up, and from it we 
have obtained the following particulars. 
In Java, 97 days of the year are stormy; in Su- 
matra, 86 days; Hindostan, 56 days; Rio de Janeiro, 
51 days; Italy, 38 days; Holland, 18 days; France, 
Austria and Russia, 16 days; Spain, and Portugal, 
15 days; Switzerland and Finland, 8 days; England, 
and Scotland, 7 days; Norway, 4 days; China, 3 
days. In Malta the average is 12 days for thun- 
derstorms, and 18 days per year for lightning. 
Prof. Duncan, F.R.S. in his interesting work on 
the “Transformation of Insects” gives the following 
decription of the life history of that troublesome, ! 
but in these regions, very familiar pest, the flea. 
Fleas lay their eggs in cracks, in cushions, and 
in boards, or in the midst of dust, and their larvae, 
which have no legs, and which therefore must live 
where they have been born, can only exist in con- 
sequence of the nourishment brought to them by 
the adults. Were they abandoned, they would 
perish, but they have excellent mothers who never 
leave them; for after a flea, should it be a mother, 
has gorged itself with blood, it seeks its young and 
disgorges a small quantity, so as to keep them 
alive. The larvae shut themselves up in silken 
cocoons when they have attained their full size, 
and undergo their metamorphosis into the condi- 
tion of nymphs. 
Among Messrs Sonnenschien’s scientific publi 
cations during the present Tutumn we note the 
following. 
The Colours of Animals. By Prof. Reddaed, 
of the Zoological Society’s Gardens and Guy’s 
Hospital, London. With Coloured and other Plates 
and Woodcuts. 
Man and Mammals. By Dr. Oscar Hertwig,' 
Professor of Comparative Anatomy in the Univer- 
sity of Beilin. Translated and Edited from the 
Third German Edition (with the assistance of the 
Author) by Dr. E. L. Mark, Professor of Anatomy 
in Harvard University. (Printed in England.) 
With 389 Illustrations and 2 Coloured Plates. 
Invertebrates. By Drs. Korschelt and Heider, 
of the University of Berlin. Translated and 
Edited by Dr. E. L. Mark, Professor of Anatomy 
in Harvard University. With several hundred 
Illustrations. (Printed in England.) 
Text-Book of Animal Paleontology. By Dr. 
Thomas Roberts, of the Woodwardian Museum, 
Cambridge. Designed as a Supplement to Claus 
and Sedgwick’s “Text-Book of Zoology”. Illustrated. 
Text-Book of Geology. Adapted from the work 
of Dr. Emanuel Kayser, Professor in the Univer- 
sity of Mar bug, by Philip Bale, of St. John’s 
College, Cambridge. With Illustrations. 
Text-Book of Zoology. By Dr. C. Claus, of the 
University of Vienna, and Adam Sedgwick, M.A. 
F.R.S., Fellow and Lecturer of Trinity College, 
Cambridge and Examiner in Zoology to the Uni- 
versity of London. Vo!. II.: Mollusca to Man. 
Third Edition. 
The many experiments that have been carried 
on in the Mediterranean for the purpose of deter- 
mining the penetrating power of light have been 
attended with some curious and interesting 
results. 
