RILEY NOTES ON THE YUCCA BORER. 335 



by any extruded sheath ; "the prevailing tints of the wings are 

 tawny and black, marked also but often feebly with pale, some- 

 times vitreous, spots" ; the antennae have a stout club, which 

 either tapers rapidly or is devoid of a crook ; the hind wings are 

 usually horizontal in rest ; the eggs are smooth, usually broader 

 than high ; and the larvae " feed on Gramineae, and generally 

 construct vertical nests among the blades." 



The eggs of the Castnians are, so far as I am aware, unknown 

 and undescribed. In both butterflies and moths they present an 

 infinite variety in form, in sculpture, and in the manner in which 

 they are laid. As a rule, however, those of the larger moths are 

 either ovoid, spherical or flattened, and rarely subcorneal or sculp- 

 tured ; while those of butterflies are more often conical, and 

 present greater variety in form and sculpture. The eggs of Hes- 

 perians are subconical, and those of the Astyci, as we have just 

 seen, in being smooth and broader than high, agree exactly with 

 those of Yucca-. 



The larva? of the Castnians are, according to Boisduval,* endo- 

 phytous, boring the stems and roots of Orchids and other plants, 

 like the Sesians and Hepialians, and like Yucccz. But they are 

 ornamented with the ordinary horny piliferous spots or warts 

 which characterize Heterocerous larvae, and have a horny anal 

 plate. Butterfly larvae, on the contrary, rarely possess these 

 warts, but frequently have the body uniformly beset superiorly 

 with close-shorn bristles as in Yuccce, such bristles generally 

 springing from minute papilla?. The newly hatched larvae of the 

 two divisions approach each other more nearly in general ap- 

 pearance, as all animals do, the farther we go back to the com- 

 mencement of individual life ; but though the newly-hatched 

 larva of Yuccce bears a general resemblance to the same stage in 

 many endophytous Heterocerous larvae (e.g. Xyleutes, Cossus), 

 yet in the stiff hairs springing from the general surface, or from 

 very minute points, instead of from distinct tuoercles, it agrees 

 with the Rhopalocera. The legs, both false and true, together 

 with their armature and the trophi, are so extremely variable in 

 both divisions that comparisons can hardly be instituted. The 

 endophytous habit, though very exceptional, is found in butter- 

 flies (e.g. Thecla Isocrates, Fabr. : see Westwood's Intr., ii., 



* Suites JiBuffon; Sfkingides, Sfct'idcs, Castniides ; Paris, 1S74. 



