Oti Heterocera from Costa Rica. 231 



is much longer and thicker and generally of a brighter 

 yellow. 



The song is also different from that of the smaller northern 

 form, and will be described elsewhere. 



Type of Ammomanes deserti mya : $ , no. 200. Oued 

 Mya, 7. iv. 1912. In the Triug Museum. 



XXIX. — New Species of Heterocera from Oosta Rica. — XVII. 

 By W. SCHAUS/F.Z.S. 



GeometridsB. 



Subfam. BoARMiiN^, 



Semiothisa lydia, sp. n. 



$ . Body brownish giey, with some darker irrorations on 

 abdomen. Wings greyish white, almost obscured by grey 

 stiicG, and some scattered black irrorations ; lines grey- 

 brown ; medial line coarse, waviiy dentate; postmedial fine, 

 lunular dentate, closely followed by a broad dull shade of the 

 same colour, reaching termen, but slightly mottled with 

 ground-colour on tennen at middle of outer margins. Fore 

 wings; a fine antemedial line angled on subcostal; a dark 

 streak on discocellular ; some white mottlings at apex. 

 Hind wings : a black discal point. Wings below whiter^, 

 mottled with grey-brown striae ; the veins yellow-brown ; 

 the lines daik brown ; the postmedial lunular and the shade 

 following it narrower; on fore wings the white ground- 

 colour is partly shaded with yellowish. Outer margin of 

 fore wing sinuous, of hind wing bluntly angled. 



Expanse 2Q mm. 



Hob. Tuis, Sixola. 



Semiothisa delia, sp. n. 



? . Very similar to S. Ii/dia, Schs. ; the outer margin of 

 fore wing more deeply sinuous, of hind wing more sharply 

 angled ; ground-colour whiter, the markings all dark brownish 

 slate-colour ; the hind wings with medial line much broader, 

 suffusing with striae to near base. Underneath the same 

 difference in colour is noticeable^ and the veins are dark 

 brown, not yellow-brown. 



Expanse 28 mm. 



JJab. Juan Vinas, Sitio, 



16* 



