732 THE GENERATIVE ORGANS. 



a very clear agreement on the part of all who have investigated 

 the subject that the male organ and the sting, or ovipositor, 

 are homologous structures. Poulton, who has recently in- 

 vestigated the development of the external organs in the 

 Lepidoptera, in which the. armature of the penis is but little 

 developed, finds the male genital armature is represented in the 

 young pupa by a single pair of papilla: behind the eighth 

 somite, probably my progenital somite, with a furrow between 

 them, which ultimately becomes a deep pit, the origin of the 

 ejaculatory duct. 



The question formerly discussed as to whether the papillae 

 (rhabdites) from which the external armature is developed are 

 true limbs or not, appears to me to have been completely 

 settled by the observations of Dewitz, and I think the view 

 held by Lacaze-Duthiers that this armature consists, in part at 

 least, of the modified sterna of the genital somites must be held 

 to be no longer tenable. 



c. Comparative Morphology of the External Generative Organs. 



The parts developed by the modifications of these abdominal 

 appendages have received different names in different insects. 

 The anterior and posterior zygapophyses (or claspers) in both 

 sexes, the valves of the ovipositor and the parts of the sting in 

 female insects, and the armature of the penis of the males are 

 highly modified structures formed from one or more pairs of 

 these appendages. Cerci are probably also lateral ventral 

 appendages of the metagenital and anal segments, but their 

 development has not been traced. Lastly, the so-called podical 

 plates are possibly merely divided sternal plates. 



The Anterior Gonapophyses are developed as a pair of papillae 

 from the posterior part of the eighth abdominal somite, my 

 progenital somite. They correspond with the inferior blades 

 of the ovipositor in the female of Locusta, and the great 

 claspers of mule Insects. They are often exceedingly complex, 

 :unl in Tipula amongst the Diptera exhibit three distinct rami 



