162 Transactions. — Zoology. 



remote. Such is the normal form in most groups of Lepid- 

 optera, and in the nomenclature of Dyar* are known as — 

 i. anterior, ii. posterior, trapezoidal tubercles. Newly- 

 hatched larvae of Bhopalocera have the primitive position 

 of the tubercles and single setae (Vanessa gonerilla, figs. 9-11). 

 After the first moult Vanessa larvae acquire by coalescence of 

 the anterior trapezoidal tubercles a single mid-dorsal unpaired 

 tubercle (fig. 12), which, with the other abdominal tubercles, 

 has numerous setae. The trapezoidal tubercles of some 

 Psychiclce (CEceticus, fig. 17) are reversed in position in 

 newly hatched and adult larvae. Some European Psychidce 

 (Taleporia) exhibit intermediate and normal position of the 

 trapezoidals. Abdominal tubercles (iii.) supraspiracular, a 

 tubercle always above the spiracle usually somewhat anterior, 

 in Geometrce (figs. 5, 6) noticeably so. The primitive condition 

 of the supraspiracular tubercle appears to be with a single 

 seta in most groups — Rhopalocera (fig. 9), Psychidce (fig. 16), 

 Noctuce (fig. 13). Hepialidce have two supraspiracular setae 

 in the newly hatched stage, which, however, appear to arise 

 from distinct separate tubercles. From its minute size the 

 anterior seta suggests the original condition of two supra- 

 spiracular tubercles and the gradual loss of one (the anterior) 

 amongst primitive Lepidoptera from which Hepialidce were 

 derived ; and it is of interest to note that the supraspiracular in 

 Tinea (pellionella, fig. 15) has two setae, one of which, as in 

 Hepialidce (the anterior), is very minute. Tinea is certainly an 

 ancient group of Lepidoptera, and its minute supraspiracular 

 seta, with its less independent base, may represent a further 

 stage in the loss of the ancestral second supraspiracular. Such 

 a form as may be observed in Arctidce of supraspiracular 

 tubercle with numerous setae (fig. 18) is unquestionably evi- 

 dence of specialisation. A closely allied genus in the same 

 group (Nyctemera annulata) has the supraspiracular and the 

 other abdominal tubercles with primitive single setae, iv. Post- 

 subspiracular tubercle usually below the spiracle in a posterior 

 position ; in some groups is moved up level with the spiracle 

 — Geometrce (figs. 5, 6), Noctuce (fig. 13), Arctidce (fig. 18). 

 v. Subspiracular in all groups with which I am acquainted is 

 below the spiracle and usually anterior, vi. A tubercle above 

 the abdominal feet is usually not present until after the first 

 moult in Psychidce (fig. 16) and Arctidce (tig. 18). In — x I have 

 observed an area probably representing this tubercle in the 

 newly hatched larvae, but the seta is not developed until after 

 the first moult. It may be noted that, whereas in Hepialidce 

 and other groups this tubercle (vi.) is anterior above the 

 abdominal feet, in Noctuce (fig. 13) it is posterior in position. 



* Classification of Lep. Larva;, G. H. Dyar, Pb.D. 



