94 MEGANOSTOMA; NATHALIS. Bij J. Sober. 



dimera. C. dimtr& Dbl.(& Hew. (= er_y throgramma A'oH.) (27 h) is likewise a mountain species indigenous to Colombia, 



Peru, Ecuador, etc., and apparently little variable. The upper surface of the forewing is orange-j'ellow, that 

 of the hindwing lemon-j^ellow. The dark margin of the forewing is moderately broad, that of the hindwing 

 somewhat variable, occasional^ it is entirely wanting, as also the black median spot of the forewing. The 

 imder surface is sulphur-yellow and has a row of reddish submarginal spots, a diffuse spot at the base and a 

 white, red-bordered median spot on the hindwing. The $ is above and beneath yellowish white. 



25. Genus: Meg-aiiostoma Beak. 



The species of this genus were formerly united with Colias. But apart from differences in neuration 

 the Meganostoma-s])ecies are even superficially characterised by the sharply pointed forewing. The $? have 

 an organ which is only observable in newly emerged specimens on account of its being so very perishable, 

 namely soft, membranous, three-jointed structures on the tarsi of the middle and hindlegs, which have been 

 named eupronechiae by their discoverer Reakirt. Their purpose is not known. Meganostoma is further well 

 differentiated from the other Pierids by the absence of a pad between the claws. The larvae live on Leguminosae. . 



eurtjdice. M. eurydice Bdv. (= 9 lorquini Bdv., wosnesenskii Meti.) (26 f) (the Cahfornian Dog-face), from Cali- 



fornia, has in the male a brilliant sheen on the upper surface only rarely occurring in Pierids. Occasionally 

 also the hindwing has a narrow black distal margin. The $ is unicolorous ^yellow with a large black median 

 spot on the forewing and reddish marginal spots. The marking of the under surface in both sexes is thoroughly 

 Colias-like. The larva lives on Amorpha californica. Egg spindle-shaped, thick in the middle, running 

 out into a rounded point, with longitudinal ribs. Full-grown larva cylindrical, of uniform thickness from 

 segment 3 to 11, densely covered with small black tubercles, on each of which a very fine black hair 

 is placed, from segment 3 to 11, a narrow white band above the legs, above this band on the 3. and 

 4. segments, in the middle of each segment, is a glassy, semicircular appendage, black with purple reflection; 

 on the remaining segments this structure is only occasionally found. Colour dark green, underside blue-green, 

 also the legs; head round, only a little depressed at the vertex, strongly covered with fine black dots, each 

 of which bears a short black hair. Pupation takes place six days after the larva ceases to feed. Pupa late- 

 rally compressed, the thorax projecting on the ventral side and forming a narrow prominence, abdomen pointed, 

 conical, mesothorax less projecting than in C. eurytheme and jjhilodice, low, rounded, with a low keel, behind 

 which there is a slight incision. Head apple-green, a white stripe at the sides of the abdomen. Duration of 

 the pupal stage nine to ten daj's. 



csonia. M. cesonia Stoll (= sesonia Mart., caroliniana Pet.) (26 f) (the Southern Dog-face) is distributed from 



the United States of North America to Argentina. The $ has reduced marginal marking, the black marking 



onides. at the distal margin of the hindwing is always absent. — cesonides Stgr., from Bolivia (3500 m), is smaller, 



^cerbera. has narrower black distal margin, and the black dusting at the base is almost entirely absent. — cerbera Fldr., 



from Venezuela, has on the under surface of the hindwing red longitudinal stripes (is doubtless only an aber- 



— ^ rosea, ration). — rosea Stgr. i. /., from Colorado, has small black stripes instead of the black distal margin of the 



^111) ^f".''"'" hindwing. — centralamericana Stgr. i. I. has very broad black margin also to the hindwing and on the latter^ 



tliernardino. orange-yellow spots before the black distal margin. — bernardino Ediv. is only a small form. ,,_..^/^^j 



IJhilippa. M. philippa J^. (26 e), from Bolivia, has in the (J the apex of the forewing rounded, in the $ on the con- 



trary it is rather pointed. In the marking there is no constant difference. 



^ciinops. M. cynops Btlr. (26 e), from Haiti, has the apex of the forewing rounded in both sexes. The^* has broad 



black margin, in the $ this is broken up into spots. 



\helena. M. Helena Beak. (26 e), from Bolivia, has, especially in the female, the forewing very sharply produced. 



The (J has no black margin to the light orange-yellow hindwing, in the $ the hindwing is hkewise without mark- 

 ings except the yellow median spot and on the forewing the margin is broken up into spots. The under surface 



, in both sexes has a considerable amount of red marking. 



\ilhcrapts. M. therapis FJdr. (26 f), from Venezuela and Cahfornia, has the forewing sharply pointed. The ^ is 



lemon-yellow, the? hght sulphur-yellow. Both have strongly reduced' distal-marginal marking and on the under 

 surface much red marking. 



Very probably the genus Meganostoma has only two species, eurydice and cesonia; all the other forms 

 described above I shoirld consider only aberrant forms or slight local modifications of cesonia. 



26. Genus: Xatlialis Bdv. 



This genus only embraces two small species, of which even the superficial appearance forbids any 

 confusion with other genera. The antennae have strikingly knob-like clubs. The palpi are rather hairy than 

 scaled and the subcostal has three branches, two of which branch off before the discocellular. 





