OXYAMBULYX. 135 



'21. Oxyambulyx canescens canescens (Walk.). (Fig. 23 E-I 

 gent alia). 



Arnbulyx canescens, Walker, 1864, p. 38 (Cambodia). 

 Oxyambulyx canescens, Roths. & Jord., 1903, p. 205, pi. ix, fig. 5 ($). 

 Oxyambulyx canescens canescens, Seitz, 1928, pp. 535, 571, t. 61 d. 

 Arnbulyx argentata, Druce, 1882, p. 17 (Cochin-China) ; Waterhouse, 

 ,1883, pi. cxxxvi, fig. 2. 



Imago.— $%. Upperside whitish-grey ; band of thorax 

 broad, three contiguous postcellular subbasal spots on fore wing- 

 besides a spot in the cell. No dorsal line on abdomen. Fore 

 tibia armed with some spines at and near the end. Hind tibia 

 a little longer (in q J mm. ; in $ 1J mm.) and its long- 

 terminal spur only about one-third shorter than the first tarsal 

 segment. Expanse : £ 98 mm., $ 110 mm. 



$. Eighth abdominal sternite deeply sinuate mesially, the 

 •edge of the segment very oblique, each side very slightly and 

 almost evenly convex from the most dorsal point to bottom 

 of sinus. The harpe (fig. 23 G) is the most peculiar in the genus, 

 it being connected with the body of the clasper only at base ; 

 it is a very long, slightly twisted process, of which the apical 

 third is rather suddenly narrowed and gently bent dorsad ; 

 the two harpes lying across each other, as shown in the figure. 

 Penis-sheath (fig. 23 H) armed apically with a process which is 

 concave ventrally and armed with some teeth at ventral 

 edge ; the process is apparently movable, being joined to the 

 penis-sheath ; ventrally another armature consisting of an 

 elongate, oblique patch of teeth a little before distal edge of 

 sheath. Tenth tergite (the supra-anal hook) (fig. 23 E, F) 

 very different from that of other Oxyambulyx, in which it 

 is uniform in structure : in canescens it is longer than elsewhere 

 in the genus, broad, mesially incised at end, and the lateral 

 edges turned ventrad a little, the upper surface of the tergite 

 being somewhat convex ; in a lateral view (fig. 23 F) it is 

 slightly curved ventrad. Tenth sternite in a ventral view 

 triangular, sharply pointed ; in a lateral view it resembles 

 somewhat the blade of a knife, the mesial line of the sternite 

 being raised into a thin but comparatively high carina, which 

 is minutely denticulate. The membrane just above the 

 anus more strongly chitinized, forming a short, smooth 

 brown bar. 



o. Eighth tergite long, truncate, not sinuate. Vaginal plate 

 (fig. 23 I) with a sinuate ante-vaginal ridge ; at each side of 

 the orifice a pointed curved process which has a rather close 

 resemblance to the armature of Polyptychus pygarga ; post- 

 vaginal part of plate small, transversely folded. 



Hob. Andaman Islands ; also Malaya and South Indo- 

 China. Early stages unknown. 



