The Segmentation of the Insect Head

The elucidation of the primitive segments in arthropods is a most interesting and difficult morphological problem. The rule of Savigny-emphasized by Huxley and others-that arthropods are fundamentally constructed of successive rings, each of which may bear but one pair of primary appendages, although now undoubted, has never been thoroughly substantiated when applied to the hexapod head. After )Tears of argument, morphologists still disagree as to the number of somites composing the highly differentiated heads of insects, Compare the latest text-books in respect to the subject. Kolbe (’9o) recognizes five, as follows: . Ursegment Ftihler Augen, Oberlippe.