1880. } Zoblogy. 897 
THE ORGANS OF SMELL IN InsEcts.—A recent number of Sie- 
bold and Kolliker’s Zeitschrift, contains an article by G. Hauser, on 
the minute structure of the sense organs in the antenne of different 
insects, which throws much new light on the functions of the an- 
tennz of insects. He concludes that the organs of smell consist 
in insects, z. e., all the Orthoptera, Pseudoneuroptera, Diptera and 
Hymenoptera, also ina large part of the Lepidoptera, Neuroptera 
and Coleoptera: 1. Of the antennal nerve; 2. Of a terminal per- 
ceptive apparatus, which consists of rod-bearing cells arising from _ 
hypodermis-cells, with which a nerve-fiber connects ; 3. Of an ap- 
paratus consisting of a pit ora cone filled with a serous fluid, which 
are to be considered as simple infoldings and projections of the 
epidermis. He then discusses the mode of evolution of these 
organs, considering the fact that the males of all orders of insects 
have more developed antennz than the females, the latter being 
the more sluggish and living in more retired and concealed 
places, while the males have more active habits, sharper senses, 
and are more likely to find the females, and thus ensure the main- 
tenance of the species. 
ACTION oF ACIDS AND COLOR LIGHT on MARINE INVERTEBRATES. 
—M. Yung has recently investigated the effects of alkaline or acid 
media on Cephalopoda, and with results pretty similar to those of 
M. Richet with crayfish. The animals are extremely sensitive to 
the action of mineral acids; where litmus hardly announces the 
presence of an acid, a young poulpe will immediately give signs 
of great pain. But more is required to prove fatal, With one cc. 
in two litres of water, sulphuric, nitric, or hydrochloric acid proved 
fatal (in from two to four and a half hours) to Eledone moschata; 
but not to oxalic acid. Sulphuric acid was the least toxical of the 
mineral acids. Of the much less energetic organic acids, tannic 
acid acts most rapidly. The alkalies range as follows in (decreas- 
ing) order of toxical power :—Ammonia, potash, soda, lime, 
baryta; the action of ammonia being extremely rapid. M. Yung, 
has also verified, in the main, for marine animals, the results of 
his former experiments on fresh-water animals, regarding the in- 
fluence of colored light on animal development; finding violet and 
blue light stimulant, while red and green retards the growth; 
yellow comes nearest to white.—English Mechanic. 
Tue THORAX oF THE BLow Fry.—An essay on this subject by 
Arthur Hammond, treats especially of the limits of the several seg- 
ments of the connate thorax of the Diptera. The author enters 
fully into the history of the different opinions relative to the morph- 
ology of the thorax, and then considers the structure of the 
thorax in other insects. He calls attention to the fact that in the 
Lepidoptera and Hymenoptera, the development of the segment is 
Proportioned to that of the wings, and shows that the same rule 
holds good in the Diptera, the metathorax being as obsolete as the 
VOL, XIV,—NO, XII. 58 
