96 MIDEA; ZEGEIS; EEOESSA. By J. Bdher. 



fj^'pima. A. pima Edw. (28 a), from Arizona, flies at the middle of March. Upper surface in both sexes yellow, 



^ the black apical marking sometimes encroaches more or less on the yellow subapical spot. Under surface of 



the hindwine vellow-ereen and marked with white. 



29. Genus: Midea H.-Sch&ff. 



( fy/i^ ' 'frciu.^JUi-' 



The principal character of this genus consists in the shape of the wings, the forewing is somewhat fal- 

 cate. The neuration is scarcely different from that of Anthocharis. It is therefore purely a matter of opinion 

 whether the following species should be added to Anthocharis or associated in a separate genus. 



A gciuitia. M. genutia F. (= midea Hbn., rherminieri Godt.) (the Falcate Orange-tip) (28 b) occurs throughout 



the United States, in the north in one generation, in the south in two. Upper surface in both sexes white with 

 black median spot and black apical markings, the 3* with orange-yellow spot in the apex of the forewing. Under 

 surface white with grey-green markings on the hindwing and the apex of the forewing. — Egg long, narrow, 

 thickest in the middle, moderately rounded towards the base, the latter broad and flattened, suddenly narrowed 

 towards the apex, so that the upper half is conical, the apex impressed, the micropyle surrounded by small, 

 irregular hexagonal cells, vertically ribbed, the number of the ribs about 16, of which half reach the tip and the 

 others terminate not far from it, the interspaces filled up by numerous fine grooves. Colour yellow-green. Dur- 

 ation of the egg-stage four days. Full-grown larva cylindrical, slender, head broad, colour dark yellow-green, 

 shiny, underside, ventral and thoracic legs lighter, a j^ellow band in the middle of the back from the 2. to the 

 13. segment, a broad white band above the legs, upperside decorated with six longitudinal rows of shiny black 

 tubercles, each with a short black hair which is thicker at the end. Pupa slender, abdomen long, round and 

 pointed, head with a pointed appendage, on the ventral side of the thorax an almost triangular, laterally com- 

 pressed lamp, which is hidden by the wing-cases; colour usually light yellow-brown with a reddish tinge and 

 darker on the mesothorax, the prolongation of the head brown, the wing-cases more or less spotted and striped 

 with black, at the back of the abdomen a row of small black spots, two to four on each segment, and a subdor- 

 . sal row of small spots or dots. 



/,V 



Vs limonea. M. limonea Btlr. (28 b), from Mexico, is much larger than genutia, has the upper surface of the hind- 



wing yellow, and the forewing is not pure white as in genutia. The marking at the apex of the forewing is rather 

 different from that of genutia. 2 



(^anceohiia. M. laticeolata Luc. (Boisduval's Marble) (28 b) is distributed from North California to Alaska, but rare. 



The upper surface is white with black median spot and slight blackish apical markings, which are enlarged 

 in the $. The under surface is sprinkled with brown, the veins especially are distinctly scaled with brown. — 

 Larva green, laterally light blue with white stripes, also with small black dots, each with a short black bristle; 

 it lives on Turritis. 



30. Genus: Zegris Bbr. 



The Palaearctic species of this genus are distinguished by their life-history. The larvae do not pupate 

 free like most other Pierids, but in a cocoon in which traces of the girdle are still present. As the larva of the 

 only American species is not yet known, it cannot be proved with certainty whether it belongs to this genus. 

 But according to the neuration and the marking of the under surface ohjmpia belongs to the genus Zegris. 



^ohimpia. Z. olympia Edw. (28 b), from Texas, is white above, with large black median spot and small, shadowy 



J apical markings. The under surface has the markings shown in the figure, which are somewhat reduced in 



f|^ros«. ab. rosa Edw. 



31. Genus: Eroessa DU. 



This genus is nearly allied to the Palaearctic and North American Euchloe and Anthocharis, in it, how- 

 ever, both the radials of the forewing are free and the cell is consequently closed by three discocellulars. The 

 forewing has slightly undulate distal margin and five-branched subcostal, the two first subcostals arise before 

 the end of the cell, the third far behind it. The precostal is directed proximally. The palpi are very slender, 

 . anteriorlv long-haired. The only species of this genus inhabits the high mountains of Chile. 



^chilcnsis. E. chilensis Guer. (28 c) has M'hite ground-colour on the upper surface, with black apical half of the 



forewing, in which is placed a large orange-red spot. The hindwing has a row of black marginal and submarginal 



