972 LORD WALSINGHAM ON THE [Nov. 26, 



It is extremely difficult to describe the differences between this 

 species and cedronellae : its smaller size, more sprinkled appear- 

 ance, and slightly yellower-white markings may alone be relied on 

 to separate them. 



I have, what I believe to be, yet a third, intermediate, species 

 of Perittia, (bystropogonis), from Guimar, feeding on Bystropogon 

 plumosus, in March, and emerging towards the end of April. 



Hdb. TEXERIFE : Guimar, Bystropogon plumosus, 27. Ill, 

 excl. 21-26. IV. 1907. Six specimens (99076-81). 



42, (384) SCYTHRIS Hb. 



84. (3478-02) SCYTHRIS ARACHNODES, sp. n. 

 (Plate LII. fig. 16.) 



Antennae black. Palpi slender, porrect ; hoary greyish, mixed 

 with black. Head and Thorax black ; face greyish. Forewings 

 short, obtusely lanceolate ; black, a few greyish white scales at 

 the base, and two transverse bands of the same, one before, the 

 other beyond the middle ; the first narrower than the second, 

 and running a little obliquely outward from the costa ; the second 

 moderately straight, both being ill-defined, with a few scattered 

 whitish scales between them, others forming a patch at the apex ; 

 cilia greyish fuscous. Exp. al. 710 mm. Hindwings dark 

 leaden grey; cilia greyish fuscous. Abdomen steely grey. Legs 

 greyish fuscous, the tarsi shaded with black. 



Type 6 (99082) ; $ (99083) ; (99084) Mus. Wlsm. 



Hob. TENERIFE : Santa Cruz, 12-20. II. 1907 (Wlsm.\ 4. IY. 

 1904 (Eaton), in webs 011 rocks, 6. I, excl. 15. II - 28. III. 

 1907 (Wlsm.) ; Cruz de Afur, 5. IY. 1904 (Eaton) ; Guimar, 

 in webs on rocks, 1. Ill - 4. IY, excl. 11. YIII. 1907 (Wlsm.). 

 Twenty-seven specimens. 



The larva feeds, probably on small lichens, ori the surface of 

 rocks, and rough stones in walls, and is very widely distributed 

 in the Island, where its webs are to be seen forming numerous 

 small patches on the face of almost every rock by the roadside. 

 They have the appearance of rather opaque spiders' webs, and 

 as they endure long after the moth has left them they are much 

 more numerous than the larvae themselves. Nearly allied to 

 bubaniae Wlsm. [Ent. Mo. Mag. XLI. 6-7 no. 3478*1 (1907)], 

 but smaller, and the fasciae are much more distinct. 



85. (3533-1) SCYTHRIS PETRELLA, sp. n. (Plate LII. fig. 17.) 



Antennae greyish fuscous. Palpi slender, porrect ; ash-grey. 

 Head and Thorax ashy grey. Forewings greyish fuscous, mottled 

 with ashy white, the base sprinkled with ashy white scales ; an 

 outwardly angulate, ill-defined fascia at two-fifths, followed by 

 more sprinkled scales, especially towards the costa, the whole 

 [62] 



