94 MEGAN08T0MA: NATHALIS. By J. Robcr. 



dimrni. C. dimera Dbl.SHeiv. (= erythrogramma Roll.) ('27 li) is likewise a mountain species indigenous to Colombia, 



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

 of the hindwing lemon-yellow. The dark margin of the forewing is moderately broad, that of the hindwing 

 somewhat variable, occasionally 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-anostoiiia L'enk. 



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

 the Meganosfoma-specieii 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 Reakikt. Their purpose is not known. Meyanostoma is further well 

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



euryiUcc. M. eurydice Bdv. (= $ lorquini Bdi\, wosnesenskii Men.) (26 f) (the Californian 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 

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

 out into a rounded point, with longitudinal riljs. 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 ))and 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. eurylheme and fhilodice, 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 days. 



ccsoniit. 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 



cetfonklcs. at the distal margin of the hindwing is always absent. — cesonides Styr., from Bolivia (3.500 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 .S7(/r. /. ?., from Colorado, has small lilack stripes instead of the black distal margin of the 



hindwing. — centralamericana Styr. i. I. has very broad black margin also to the hindwing and on the latter 



beniardino. orange-yellow spots before the black distal margin. — beriiardino Kdw. is only a small form. 



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



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



cynops. 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. 



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



The ^ has no black margin to the light orange-yellow hindwing, in the $ the hindwing is likewise 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. 



thempis. M. therapis Fldr. (26 f), from Venezuela and California, has the forewing sharply pointed. The ^J is 



lemon-yellow, the $ light sulphur-yellow. Both have strongly reduced distal-marginal marking and on the under 

 surface much red marking. 



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

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



26. Genus: Natliali)^ 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. 



central- 

 americana. 



