2 Annals Entomological Society of America [Vol. XV, 



to me or was received too late to be of use in the preparation 

 of Part I.* 



Since this part was published I received copies of two short 

 papers by L. Chopard, entitled "Notes preliminaires sur la 

 conformation de I'extremite abdominale des Orthopleres" and 

 "Note prehminaire sur la conformation de I'organe copulateur 

 des Orthopteres, " published in 1917 and 1918, respectively. 

 Still later, when the present work was nearly finished, I received 

 a copy of the same author's fuller treatise entitled "Recherches 

 sur la conformation et le developpement des derniers segments 

 abdominaux chez les Orthopteres," published in 1920. In this 

 extensive and valuable work a very large number of forms are 

 discussed and much of my own work has been anticipated. 

 The general conclusions as to the typical structure of the 

 terminal segments in Orthopteroid insects and the male 

 homologies of the parts of the ovipositor are quite in accord 

 with my own, but naturally there are some matters on which 

 our views are not quite in agreement. - Some reference has been 

 made to these in the following pages, but unfortunately Mons. 

 Chopard' s work was received too late to give it the consideration 

 that it deserves. 



GENERAL MORPHOLOGY. 



As in the female Pterygote insect, there is also in the male 

 usually a single genital aperture, which, however, has a different 

 position, namely in the membrane between the ninth and tenth 

 abdominal sterna, f though sometimes apparently on the ninth 

 sternum itself. This aperture is typically formed by an 

 invagination of the body wall, into which open the two primitive 

 ejaculatory ducts, the invagination forming a common terminal 

 passage, which itself is usually termed the ejaculatory duct. 

 In the Ephemerida and Dermaptera, however, this invagination 

 does not take place, and although in the latter order the genital 

 aperture is frequently single, it is due either to the abortion 

 of one of the openings or to the fusion of the terminal parts of the 

 two ducts. The aperture is usually borne upon an outgrowth, 

 the penis or aedeagus, whose walls may be more or less 



* Ann. Ent. Soc. Amer., XII, No. 4, Dec, 1919, pp 267-316. with Pis. XX- 

 XXVIII. 



t I. e., the sterna of the 9th and 10th abdominal segments, whether the 

 sternum of segment 1 is present or not. 



