Structure of Permian Homoptera and Psocoptera

Abstract

THE recent note in NATURE¹ on the ancestors of some groups of existing insects prompts me to mention certain facts apparently overlooked by Prof. G. Zalessky, and to direct attention to others bearing on the subject. Zalessky announces his discovery that the Permian Psocoptera had a “proboscisshaped” head, provided with a sucking apparatus similar to that of the Homoptera. In 1933² I gave a detailed account, which is not mentioned by Zalessky, of the body structure of the Kansan Permian Psocoptera, and demonstrated then (Fig. 13, and plate 1, Fig. 4) that the head possessed a prominent rostrum. The significant feature of the rostrum of these Psocoptera is the presence of large and generalized maxillary and labial palpi, which are scarcely suggestive of the structure of the piercing beak of the Homoptera. Zalessky also states that he doubts the correctness of Dr. R. J. Tillyard's description of the chewing mouth-parts in Psocidium. This description I corrected in 1932³ and at the same time showed Psocidium Till, to be a synonym of Dichentomum Till., as it was later regarded by Dr. Tillyard⁴.