Insects Have Delicate Eyes.

Star (Christchurch), Issue 19036, 3 April 1930, Page 6

Insects Have Delicate Eyes.

Nature Notes.

By

James Drummond.

F.L.S.. F.Z.S.

People who become closely acquainted with insects are amazed at the complexity and the delicacy of the little creatures' eyes. It is believed that insects have special ocular brains, brought by a remarkable complex apparatus into relation with the lights, shades and movements of the outside world. They have two sorts of eyes, simple and compound. Simple eyes vary in number from one to eighteen or twenty. As the simple eyes are very convex, they have a short focus. They can be used for only very close objects, perhaps within an inch. They seem to be used more to judge the intensity of light than for distinct vision. The compound eyes are more remarkable than the simple ones. Some entomologists regard each compound eye as an immense mass of single lenses, packed close. The little silver-fish, a household insect introduced into New Zealand, where it indulges its taste for sugar and starch as readily as in the Old Country, has twelve lenses in its compound eye; an ant has fifty; a housefl}’- 4000; a large dragonfly has 20,000; the hawk-moth, Sphinx convolvulus, whose handsome body, grey with roseate, black, and white stripes, may be seen in New Zealand, has 27,000. The tiniest insects whose eyes have been examined have lenses about one twothousandth of an inch in diameter.