Taxonomic value of Genital Armature in Lepidoptera. 327 



with the two preceding genera ; the lower tubular portion 

 is very simple, the mere tube being entirely visible in the 

 figure (PL LXII, fig. 30). The clasps are bluntly ovate with 

 long fine hairs in fair abundance, but quite difi'erent from 

 Aegeria, being arranged as is generally common to these 

 organs. The aedoeagus is long and thick, with a vesica 

 that is heavily clothed with fine bristles. The girdle is 

 more primitive than in Aegeria, whilst the saccus is almost 

 absent. 



If we compare Orenaia and Titanio we still find differ- 

 ences of sufficient importance to at once separate them, 

 with the expectation of their belonging to difterent genera. 



Orenaia has the tegumen — as represented by rupestralis 

 and alpestralis — with the uncal extremity produced for- 

 wards in a long narrow horn, with a second miniature horn 

 below it sharply serrated on its upper edge, the anal tube 

 lying between these two horns ; the tergite armature is 

 thus complete, but it is strongly attached by a short girdle 

 to the sternite section, which consists of clasps and aedoeagus, 

 the former being broad, of uniform width, the apical 

 third being densely provided with very long hairs ; the 

 aedoeagus is a long tube of even width obtusely angled at 

 a third from the apex ; the vesica is almost entirely covered 

 with fine short teeth, which are horizontally placed as it 

 lies at rest, but would of course be at once elevated under 

 excitement. In Titanio schrankiana the tegumen becomes 

 (by fusion) almost a part of the girdle, as it does generally 

 in the higher orders, viz. the Rhopalocera; the dorsal area 

 (of the tegumen) is broad and long w^ith a distinct dividing 

 line along the centre, though it is not apparently split 

 into two divisions ; the front apex being slightly incised 

 in the centre, within the hollow thus made lies a broad 

 horn-hke structure serrated at its apex. The clasps are 

 exceedingly broad, broad enough to envelope the whole 

 armature, and furnished with long hairs at the apical end ; 

 the aedoeagus is a highly curved broad tube. 



It will thus be seen that though the two armatures are 

 closely allied (the insects were put in the same genus until 

 comparatively recently), the great difference in the tegumen 

 would at once lead one to suspect that they belonged to 

 different genera. 



The genera Cossus and Duomitus are very closely allied 

 indeed; the tegumen in general shape and structure is 

 quite similar; it is not tubular, but is divided into two 



