66 The American Naturalist. (January, 
ENTOMOLOGY.’ 
* Sight in Insects.—In his recent address as President of the Bio- 
logical Society of Washington, Dr. C. V. Riley? said: “Of the five 
ordinary senses recognized in ourselves and most higher animals, 
insects have, beyond all doubt, the sense of sight, and there can be 
as little question that they possess the sense of touch, taste, smell and 
hearing. Yet, save, perhaps, that of touch, none of these senses, as 
possessed by insects, can be strictly compared with our own, while there 
is the best of evidence that insects possess other senses which we do 
not, and that they havesense organs with which we have none to com- 
pare. He who tries to comprehend the mechanism of our own senses 
—the manner in which the subtler sensations are conveyed to the 
brain—will realize how little we know thereof after all that has been 
written. It is not to be wondered at, therefore, that authors should 
differ as to the nature of many of the sense organs of insects, or that 
there should be little or no absolute knowledge of the manner in which 
the senses act upon them. The solution of psychical problems may 
never, indeed, be obtained, so infinitely minute are the ultimate atoms 
of matter; and those who have given most attention to the subject 
must echo the sentiment of Lubbock, that the principal impression 
which the more recent works on the intelligence and senses of animals 
leave on the mind is that we know very little, indeed, on the subject. 
We can but empirically observe and experiment and draw conclusions 
from well attested results. 
Sight.—Taking first the sense of sight, much has been written as to 
the picture which the compound eye of insects produces upon the brain 
or upon the nerve centers. Mostinsects which undergo complete meta- 
morphoses possess in their adolescent states simple eyes or ocelli, and 
sometimes groups of them of varying size and in varying situations. 
It is difficult, if not impossible, to demonstrate experimentally their 
efficiency as organs of sight; the probabilities are that they give but 
the faintest impressions, but otherwise act as do our own. The fact 
that they are possessed only by larve which are exposed more or less 
fully to the light, while those larve which are endophytous, or other- 
wise hidden from light, generally lack them, is in itself proof that they 
perform the ordinary functions of sight, however, low in degree. In 
1 Edited by Clarence M. Weed, New Hampshire College, Durham, N. H. 
2 Insect Life, VII, p. 33. 
