Mar. 1899-] DyAR : LiFE- HISTORIES OF N. Y. SlUG CATERPILLARS. 61 



THE LIFE-HISTORIES OF THE NEW YORK SLUG- 

 CATERPILLARS.— XVIII. 



PLATE I, FIGS. I-IO. 



By Harrison G. Dyar, A.M., Ph.D. 



Natada nasoni Grote. 



1876 — Sisyrosea nasoni Gkote, Can. Ent. VIII, 112. 

 > 1882 — Lima codes rude Hv. Edwards, Papilio, II, 12. 

 ' 1887 — Perola daona Druce, Biol. Cent.-Am., Lep. Het. I, 219; pi. 23, f. II. 



1892 — Sicyrosea nasoni and rude, KiRBY, Cat. Lep. Het. I, 554. 



1892 — Perola daona KlRBY, Cat. Lep, Het. I, 532. 



1894 — Sisyrosea nasoni Nkumoegen & Dyar, Joikn. X. Y. Ent. Soc. II, 70. 



Larva. 

 1878 — Glover, 111. N. Am. Ent. pi. 11, fig. 9. 

 1898— Dyar, Psyche, VIII, 173. 

 1898 — Beutenmuller, Bull. Am. Mus. N. H. X, 395. 



Special Structural Characters. 

 Dorsal space broad, even, a very little narrowed at either end, 

 widest centrally, though almost perfectly uniform, flat ; lateral space 

 broad, steep, almost perpendicular, straight, not concave nor flared at 

 base, of uniform width, rounded, narrowed to the terminal joints 3 

 and 13 ; subventral space strongly retracted and so short that the 

 lateral horns almost touch the leaf. Outline a parallelogram, slightly 

 rounded, scarcely elliptical. Ridges slight, indicated by the horns. 

 These are flexible in the subdorsal row, bent outward at will, normal 

 in arrangement for the spined Eucleids, short, thick and rounded. 

 The subdorsal horns extend at an angle of 45° when erected, those of 

 joints 3 to 5 being larger than the rest except that of joint 13 which 

 is longer and more slender. Lateral horns horizontal, those of joints 5 

 and 1 2 slender and longer than the subdorsals of the same segments, 

 markedly shortened at the last moult. The spines on the horns are 

 of the normal stinging type after stage I, but not very numerous, while 

 the marginal ones are club-shaped and setiferous. Those on the large 

 horns are stained with black pigment, some even banded black and 

 white. In stage I the horns are surmounted by a central swollen- 

 tipped seta and a series in a circle as in Sisyrosea textula on the an- 

 terior and posterior segments, but centrally reduced to three setre of 



