114 Annals Entomological Society of America [V^ol. XI, 



Haase, much later, also stated that the gonapophyses were not 

 true appendages, but, to translate, "integumental structures of 

 a somewhat higher order than styles," meaning those styles 

 which are inserted at the bases of the legs, in the coxse of some 

 Myriapods and Thysanura. Grassi in 1889 held a similar view. 

 According to Wheeler, all these investigators based their con- 

 clusions solely upon comparative anatomical data. The fol- 

 lowing investigators, however, have regarded these appendages, 

 genitalia or gonapophyses, as homologous with the true, so-called 

 "ambulatory," "segmental," or "pedal" extremities, although 

 they have differed a good deal in the details of their explana- 

 tions: Weismann in 1866; Kraepelin in 1872; Kowalevsky in 

 1873; Dewitzin 1875; Huxley in 1877; Cholodkovsky in 1891; 

 and Wheeler in 1893. 



Korschelt and Heider state their point of view as follows: 

 "We are here led to ask to what extent the external genital 

 appendages, the so-called gonapophyses, are to be traced back 

 to limb rudiments. The researches of Kraepelin and Dewitz 

 have revealed that the ovipositors of the Hymenoptera and the 

 Locustid^, and the corresponding genital appendages of the 

 male in these forms, are derived from the imaginal discs of the 

 eighth and ninth abdominal somites, which, when they first 

 appear in the larva, closely resemble the imaginal discs of the 

 larva of Corethra, which yield the thoracic limbs." (p. 371.) 

 Biitschli and others have therefore attempted to refer the gona- 

 pophyses of these forms to true, abdominal limb-rudiments. 

 "In support of this assumption, we might point out," continue 

 Korschelt and Heider, "that these imaginal discs develop from 

 the abdominal rudiments present in the embryo." "It should, 

 however, be mentioned," they assert, "that Haase, following 

 Uljanin, has recently opposed this view, although, as it appears 

 to us, with insufficient reason, maintaining that the gona- 

 pophyses should be regarded merely as secondarily acquired, 

 external appendages." 



Heymons is one of the strongest opponents of a homology 

 between the genital appendages and the anlages of the seg- 

 mental ambulatory ones of the embryo and the appendages of 

 an ancestral form. He states in a resume published in 1899 that 

 after embryological investigations on a great number of species 

 of Locustidae, Gryllidae, and Hemiptera, he has come to the 

 conclusion that it is a fundamental principle, in the study of 



