262 Proceedings of the 



ribbed, like those of the Noctuina; and the young larva, when first dis- 

 closed, arches the central segments slightly in walking, like nearly all the 

 larvae of the Noctuina, before their second moult. The eggs of Brephos 

 Parthenias, which Guenee places at the end of his first section of the 

 Noctuina, are oblong-oval, smooth, and resemble the eggs of most of the 

 Geometrina ; while those of Semioscopis Avellanella are flat and scale- 

 like, indicating a close affinity with the Tortricina. The young larvae 

 of Petasia nubeculosa were disclosed from the egg about the middle of 

 May, and were then bluish-gray, with small dark tubercles, and an amber- 

 coloured head. They were very restless at first, and it was some time 

 before they commenced to feed. They changed their first skin in about 

 fourteen days, spinning a silken carpet on the leaf, in which they fastened 

 their prolegs for security of position, and then appeared of a pale green, 

 with three whitish lines, minute black tubercles, and translucent green 

 head ; the thoracic feet, and a spot upon each of the prolegs black. They 

 still looped slightly in walking ; resting solitarily on the under sides of 

 the birch leaves, with their heads stiffly recurved, like the larva of En- 

 dromis versicolor ; and dropping, when suddenly alarmed, by a silken 

 thread, which they used for the purpose of regaining their position, when 

 the supposed danger was over. In disposition they were most pugnacious 

 and irritable ; hitting and biting each other whenever they came in con- 

 tact, and wandering restlessly about when disturbed. In consequence of 

 these habits, several of them died from the wounds they received from 

 their companions. The second moult was completed in eleven or twelve 

 days, when the black tubercles became pale whitish- yellow. After the third 

 moult, which was again accomplished on the fourteenth day, the young 

 larvae were pale yellowish-green, the hair- warts sulphur-yellow: an oblique 

 lateral streak on the fourth segment, and a transverse bar on the twelfth 

 segment, of the same colour ; head unicolorous green ; thoracic feet, 

 and a spot on each of the prolegs black. After this they did not appear 

 to alter much in the succeeding moults, and I was prevented from com- 

 pleting my observations upon these interesting larvae, by the demise of 

 the last one, before it was full grown ; but some of the English entomolo- 

 gists were more successful, and, I believe, obtained the pupae. 



II. On the Chalk Flints of the Forth. By Professor Fleming. 



The author stated, that having visited the Black Rocks, Leith, on the 

 28th ult., at a low ebb-tide, after strong easterly winds, he was surprised 

 to find a large heap of Chalk Flints, from which the covering of sand had 

 been removed by ripple action. Similar flints had been observed by Mr 

 Christie of Hawkhill, in a field to the eastward of the house, and the author 

 had detected a single nodule in the brick-clay of Kinghorn. Having 

 previously observed a bed of flints, with angular masses of chalk, in the 

 middle of a deposit of brick-clay, on the Aberdeenshire coast, he discarded 



