Taxonomic value of Genital Armature in Lepidoptera. 329 



a very ample vesica, that is provided copiously with fine 

 short bristles. Comparing this with Scioptera plumistrella 

 (a fairly close ally) the difference is marked; the tegumen 

 is quite small, equally simple ; the ventral plate is strongly 

 bifid; the clasps are small, but by no means so primitive, 

 being incised at the fore extremity into two lobes, some- 

 thing after the manner of the Plebeidae ; the aedoeagus is 

 much shorter, and much broader ; the vesica must be very 

 weakly developed as I cannot trace it in any of my prepara- 

 tions. In Oreopsyche atra, L., the tegumen is quite different 

 in shape, being produced forwards along the middle dorsal 

 line ; it is almost double the size of Scioptera, though not 

 nearly so large as in Psyche, being confined practically to 

 the tergite, whilst the sternite is wholly occupied by a 

 very large ventral plate covering the whole sternite and 

 having a long saccus at the rear; within this lie the two 

 clasps something similar to Scioptera, but with the upper 

 lobe much produced, whilst the aedoeagus is a small simple 

 tube. In addition to these very marked characters the 

 seventh and eighth segments are clothed with a collar of 

 formidable spines. 



PacJiytelia unicolor is closely allied to Oreopsyche as to 

 the tegumen and ventral plate, but both are very large ; 

 the clasps are large also with apices very similar to the 

 lobster's claw, whilst the aedoeagus is unusually large, both 

 long and broad and with a rather extraordinary globular 

 vesica. I would draw attention to the fact that there is 

 no girdle in this group. It will be seen that even here 

 where we might have looked for great modifications the 

 armature gives very valuable Taxonomic guidance. It was 

 necessary, of course, to confirm this by reference to other 

 groups with what we term, somewhat loosely perhaps, 

 apterous females, I therefore referred to Heterogynis 

 penella, Hb. 



In this family the tegumen is again the strongly developed 

 portion, but here it is more than a mere covering hood; 

 the tegumen is developed as the tegumen, but without the 

 girdle proper, though there is what may be the first sign 

 of it in the narrow ventral collar at the base of the tegumen. 

 It (the tegumen) is well developed laterally and dorsally 

 and has a peculiar uncal process that is strongly hooked, 

 there being one strong short hook at the apex with two 

 shorter ones at the back; the clasps appear to be absent, 

 but I think are not so in reahty, but have merely altered 



