180 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
more sensitive to the rays at some periods of development than they 
are at others. A comparison of short non-lethal exposures with 
continuous cytolyzing doses suggests that one of the effects of the light 
is to form a phototoxic substance which is cumulative in its effects. 
The effect of the rays in small doses is frequently spoken of as stimula- 
ting, but the experiments on Limnseus show that the stimulus is 
katabolic in character. There is not the same recovery curve as in 
Paramecium. J. A. T. 
Phototropism of Land Snails. — G. C. Wheeler (Comparative 
Psychology, 1921, 1, 149-54, 1 fig.). Experiments show that Helix 
aspersa is negatively phototropic, at least at certain intensities of light. 
The photo-receptors are in the eyes at the ends of the dorsal tentacles. 
The snails are not dermatoptic. The eyes are sensitive only to light 
falling in a particular direction on the ends of the tentacles. The eyes 
probably function as direction-eyes only. Yung’s experiments, which 
led him to regard the eyes as functionless, do not prove more than that 
the eyes are of no special value as image-forming eyes. J. A. T. 
Arthropoda. 
a. Insecta. 
Mutations in Bar-eye Series of Drosophila melanogaster. — 
Charles Zeleny (Journ. Exper. Zool., 1921, 34, 203-33, 5 figs.). A 
bar is a constriction of the full eye, and ultra-bar is a separation into 
two parts. There are three definite stopping-places without inter- 
mediates. All possible jumps between these stopping-places have been 
seen except full to ultra-bar. Reverse mutations are more frequent than 
the original direct ones. Full derived by mutation from bar or ultra- 
bar does not revert. There is no evidence of periodicity in the muta- 
tions. They occur in the germ-plasms of both sexes. They are not 
confined to a single period in the germ-cell history. The changes in 
the gene which produce the somatic series full to bar to ultra-bar are 
probably not of a quantitative nature. The different components of the 
bar series are definite entities comparable to definite chemical compounds 
or physical states. J. A. T. 
Protection against Blowflies.— -R. A. Wardle (Ann. Applied 
Biology, 1921, 8, 1-9). An account of numerous experiments in 
saving meat commodities from blowflies. There are a few repellent 
substances of some value that can be applied to the meat, e.g. a 
proprietary article called “Milton.” Pepper, powdered chalk, and 
powdered boracic acid are of use as long as they remain dry. Other 
substances which cannot be directly applied may be useful repellents, 
e.g. for a short time, eucalyptus oil, formic acid, and sometimes clove oil. 
The most effective oil repellent seems to be oil of aniseed smeared on to 
cotton netting. J. A. T. 
Beetles and Bugs in Tachigalia petioles. — W. M. Wheeler 
(Zoologica, 1921, 3, 35-126, 5 pis.). The swollen petioles of this 
Leguminous tree are entered, in the young shade forms, by beetles 
