726 THE GENERATIVE ORGANS. 
anatomy of the female generative armature. At the time he 
wrote the importance of embryological investigations in elu- 
cidating homologies was less understood than it is at present, 
and he did not even attempt any study of the manner in which 
these parts are developed. Lacaze-Duthiers’ most important 
generalisations were : 
(1) The external orifice of the sexual duct is very generally 
situated between the eighth and ninth abdominal segments. 
(2) The stings and ovipositors of all Insects conform in their 
general plan of structure, and exhibit homologous parts. 
(3) These parts are mainly formed by a modification of the 
sclerites forming the ninth abdominal somite, and are not 
homologous with ventral appendages, abdominal feet. 
With regard to Lacaze-Duthiers’ first generalisation, it is 
apparently correct, but owing to the confused nomenclature of 
the abdominal segments and the extensive modifications which 
the posterior segments undergo, the statements of other inves- 
tigators appear to show that there is no constancy in the 
position of the external generative orifice. 
His second generalisation is indubitably correct, although 
in matters of detail there are considerable discrepancies in the 
views which have been propounded by different writers on the 
subject. 
The third generalisation is, I think, undoubtedly erroneous. 
Huxley, in 1877, wrote :* ‘Thus it would appear that, while 
there can be no doubt as to the general unity of plan of ovi- 
positors and stings, the view of Lacaze-Duthiers must be 
modified. It must be admitted that these apparatuses apper- 
tain to the eighth and ninth somites, and not to the ninth 
alone; and that there is reason to suspect that their chief 
constituent parts are modified limbs.’ Such modified limbs 
are usually termed gonapophyses. 
Comparison of the Male and Female Genital Armature.—With 
regard to the male organs of copulation, Krapelin [874], who 
examined the development of these parts in the Drone, and the 
modifications found in hermaphrodite Bees, is led to the con- 
* ©The Anatomy of Inyertebrated Animals,’ London, 1877, Pp: 433. 
