PSYCHE 



VOL. XVIII. FEBRUARY, 1911. No. 1 



ON THE HOMOLOGIES AND MECHANISM OF THE 

 MOUTH-PARTS OF HEMIPTERA. 



By F. Muir and J. C. Kershaw, 

 Mossman, North Queensland. 



PART I. The Homologies of the Mouth-parts . 



The morphology of the head of Hemiptera has received several 

 interpretations, some writers maintaining that there are no traces 

 of mandibular structure, while others consider the outer pair of 

 seise as the mandibles, and the inner pair as the maxillae, but 

 most writers agree in considering that the setae are sunk into the 

 head-capsule. One of the authors in a former paper ^ endeavored 

 to show that in Pyrops candelaria the mandibles were present and 

 articulated in their normal position, viz., to the head-capsule, 

 between the clypeus and the maxillae, and that the maxillae are 

 present in the form of two large plates in intimate contact vnih the 

 maxillary setae. In the present paper the authors have endeavored 

 to show that the same interpretation holds good for other Hem- 

 iptera, and also that the frons, clypeus and labrum of many 

 systematists are, in many families, respectively the clypeus, 

 labrum and epipharynx. 



If the head of a Cicada (Fig. 1) be softened in water or caustic 

 potash the groove (ms) along each side of the anterior part of 

 the head will prove to be a distinct suture, whose edges are pressed 

 closely together, but neither cemented nor joined by membrane. 

 We will call this the "mandibular suture." At the posterior end 

 of this suture are articulated, by a true ginglymus articulation, the 

 mandibular setae (art. man. s.). The dorsal surface between these 

 two points will be the clypeus or clypeal region {cl r.). The posi- 

 tion of the articulation of this seta enables us to homologize it 



lA Memoir on the Anatomy and Life-History of the Homopterous Insect Pyrops candelaria. 

 J. C. Kershaw. ZooL Jahrb. Abth. f. Anat.: XXIX, p. 105-124. 



