Taxonomic value of Genital Armature in Lepidoptera, 325 



they are not in reality closely allied, but that the more 

 speciahsed genera (we cannot say dominant, for Colias is 

 a decidedly dominant group), which are now so numerous, 

 may have developed along somewhat parallel lines. Under 

 both sets of circumstances and conditions, however, we 

 have characters of great Taxonomic value. 



If we now turn to the Heterocera we shall find our con- 

 tention demonstrated yet more. We will go low down 

 and examine that interesting family so long called the 

 Sesiidae ; the prominent character of the group is that the 

 male armature (it is confined to the male sex) is provided 

 with copious brushes of long hairs, fixed into the organs 

 exactly after the manner of a hair brush except that the 

 bristles are attached individually to the chitinous wall. 



In Trochilium apiforme, these bristles are confined to 

 the edges of the clasps — instead of being spread evenly 

 over the whole inner surface — and the bristles are different ; 

 in T. apiforme they are long large spikes, attached directly 

 to the chitine, not on a tubercle, constricted at the attach- 

 ment, but immediately expanding very shortly and then 

 tapering gradually to a point ; they are confined to the 

 front apical edge, and extend in considerable numbers 

 around the fore half of the upper edge of the clasp. Another 

 character of the group (possibly pointing to the persistence 

 of the original type of these organs) is that the armature 

 is practically in two sections, viz. sternite and tergite, the 

 former being angled rearwards, whilst the latter is slightly 

 fused on to the fore extremity of the angled apex ; the 

 tegumen thus loses the typical girdle, becoming practically 

 a separate section (forming the anus with its own separate 

 channel), but being just fused as already mentioned with 

 the sternite at the one point only. In this case the tegumen 

 is almost tubular, the apex of the dorsum being well 

 excavated, whilst the cheeks are furnished with the spikes 

 already referred to ; below these are two prominent wedge- 

 shaped falces. The clasps are large and broad, and are 

 curtained over at the front apex, leaving only a deeply 

 hollowed circle for the extrusion of the aedoeagus, which 

 is very large; the vas deferens is densely covered with 

 minute teeth, and the vesica furnished apparently with a 

 rosette of the large spikes previously described. The 

 juncture of the clasps with the girdle is very shght, again 

 indicating the primitiveness of the structure. 



These organs are very different from Aegeria, where we 



TRANS. ENT. SOC. LOND. 1914. — PART II. (OCT.) Y 



