268 U.S. NATIONAL MUSEUM BULLETIN 25 7 



Hindwing with veins la and lb close together and parallel, strongly 

 excurved and approaching Ic in middle, 2 from middle of cell, 3 from 

 well beyond middle, sometimes hyaline patches between lb and Ic, 

 or between bases of 2 and 3, and 3 and 4, 4 from angle, 5 and 6 stalked, 

 connate or approximated, 7 parallel. 



Genitalia of the two sexes as described for the type species below. 



The large, long-legged species are strongly attracted by light. 

 Therefore, they are usually present in most collections. Only two 

 species, G. captiosella (all through tropical Asia?) and G. dracuncula 

 Meyrick (Andamans) have been described before. However, the 

 varied-looking "captiosella" may prove to contain several distinct 

 species when the genitalia will be studied. The larvae bore in de- 

 caying wood. 



Key to the Philippine Species of Gerontha 



1. Head and palpus white; forewing with a white spot in disc at 2/3. 



G. nivicaput, new species 

 Not thus 2 



2. Hindwing transparent, with fuscous veins and suffused margin 3 



Hindwing not transparent 4 



3. Forewing strewn with numerous irregular dots of diverse size, tending to form 



transverse fasciae; several larger dots G. captiosella 



Forewing with less numerous fine dots and a single larger spot at 2/3 of 

 costa G. monostigma, new species 



4. Head and thorax pale grey, palpus mixed with white. 



G. captiosella f. capna, new form 

 Head, thorax, and palpus fuscous G. diascopa, new species 



Gerontha captiosella Walker, 1864 



Figures 415-420, 764 



Gerontha captiosella Walker, 1864, List Lepidopterous Insects British Mus., 

 pt. 29, p. 782 (9, Ceylon). — Walsingham, 1887, in Moore, Lepidoptera Cey- 

 lon, vol. 3, p. 521 (Ceylon). — Fletcher, 1933, Imp. Counc. Agric. Res., 

 Sci. Mon., no. 4, p. 80, pi. 72 (Ceylon, India). 



Distribution: Ceylon, India, Sumatra, Java, Andaman Is., North 

 Austraha. 



Material examined: Luzon, Mt. Makihng (Baker), 1 cf, 2 9. 

 Mindanao, Surigao, V.1915, IX.1916. 18 cf , 5 9 (USNM). Zam- 

 boanga del Sur, 11 km NW of Milbuk, 390 m, 5.VIII.1958 (H.E. 

 Milliron), 1 9 (BMH). 19 cf , 8 9. Genit. sUdes 5270, 5273cf ; 5269, 

 52739. 



Considerably varying as to the size, while the neuration varies 

 only slightly: in the forewing vein 2 may be connate with the stalk 

 of 3 and 4 or out of this stalk at different distances from the lower 

 angle of cell; the same is the case with vein in reference to the stalk 

 of veins 7 and 8 and the upper angle of cell. In the hindmng veins 



