1887) Zoology. IIQ 
Senses of Insects.—M. A. Forel" contributes a most interest- 
ing and exhaustive account of experiments made by himself and 
many others on the much-discussed problem of the senses of 
insects. 
(1) In regard to the sight of ants, he notes especially these 
three conclusions: (a) They perceive light, and particularly 
ultra-violet (Lubbock); (4) they really see the ultra-violet rays, 
_ without eyes they are almost indifferent to them, and only re- 
= spond to solar light more or less intense; (c) the dermatoptric 
sensations are feebler among the ants than in the animals whic 
Graber studied. 
2) After reviewing new and old experiments as to the sense 
of smell in insects, he notes the following general facts: (a) In 
_ Many insects which are essentially directed by sight, as in the 
Libellulids and Cicadas, the antenne are rudimentary, and the 
Sense of smell likewise. During the night these insects are 
passive, while during the day they trust to their power of sight, 
or possibly, in some cigalids, also to hearing; (4) the sensitive 
region, in spite of Graber’s protestations, is situated in the anten- 
næ, especially in those parts where the antennary nerve ramifies ; 
(c) in certain insects, as in most Diptera, the antenne serve almost 
solely for smelling purposes; (d ) in other cases, however, where © 
they are mobile, as in the Hymenoptera, they are used for detecting 
their food or their mates at great distances. 
(3) As distinct organs of caste, M. Forel regards the nervous 
terminations (2) on the proboscis of flies (Leydig), (4) on the 
Jaws and on the base of the tongue (Meinert), (c) on the end of 
Ow. im (Forel), and (d) on the palate or on the epipharynx 
olf). 
(4 and 5) Forel’s results as to hearing are, as yet, too negative 
to admit of notice. He finally discusses the sense of touch in 
its various manifestations, and the last chapter of his interesting 
_ Memoir discusses the relation of the five senses to the general 
_ Psychical life of insects.— Sour. Roy. Micr. Soc., 1887, p. 577- 
ZOOLOGY. 
__, Fresh-Water Sponges.—The Proceedings of the Philadelphia 
: Academy of Natural Sciences for this year contain Mr. ard 
