Taxonomic value of Genital Armature in Lepidoptera 317 



recurved, this recurving being much finer and tapering 

 downwards to the apex. The girdle is bent forwards, not 

 erect, and has a broad lobe directly behind the lobed 

 portion of the tegumen. 



Two other allied genera lalmenus and Pseudalmenus 

 are very close to each other, but their separation is quite 

 justified by the armature ; in the former, lalmenus evagorus, 

 the tegumen is hood-shaped and all in front ; in the latter, 

 Pseudalmenus myrsilus, it is very largely truncated in 

 front with a considerable backward projection, whilst the 

 clasps are formed absolutely diversely in their whole char- 

 acter. On this latter point it should always be borne in 

 mind that clasps may differ and show merely specific 

 differences, but a total change in form and outline, whilst 

 of secondary taxonomic importance to the tegumen, yet 

 has a real value when taken with other details. 



In the Gerydinae the male armature at once shows 

 marked generic differentiation. In this group is found a 

 complete inversion of the usual characters. In Gerydus leos 

 and all other species of the genus the clasps are relatively 

 quite insignificant, not that this has been developed so much 

 by a reduction in size of these organs (though in comparison 

 with other families they are rather small), but by the im- 

 mense development of the tegumen ; this section of the 

 armature is very unusual, the dorsal bridge is reduced to 

 an extremely narrow ridge, whilst the two lateral cheeks 

 or lobes are produced and enlarged into two long razor- 

 shaped blades that when withdrawn into the abdomen 

 occupy more than two-thirds of the abdominal length ; 

 the falces or hooks are placed beyond the middle of the 

 blades rather nearer the apex, they are long and strong with 

 a sharp robust S hook at their extremity, their action is 

 secured by a strong chitinous muscular attachment with 

 the front apex of the blade which is specially strengthened 

 for this purpose. The aedoeagus is a short plain tube, 

 tapering to a fine point, the orifice extending backwards 

 for nearly half its length and partaking of the taper already 

 referred to, the clasps are small and shortish somewhat 

 boat-shaped tapering to a blunt point, with the upper 

 apical edge densely fringed with long hairs for nearly half 

 its length, with a patch of hairs on its lower part also. 

 The internal area of the blades of the tegumen is hkewise 

 clothed thickly with soft hairs. The African genus 

 Megalopalpus belongs to this family and not to the 



