PIERIS. By J. RoBER. 59 



P. napi L.. altliough distributed over the whole of Noi-th America, is much rarer there than in the napi. -y"^ 

 PaUiearctic Region. The summer form iiapi differs from the spring form oleracea Harris by more abundant oleracea. ■^/' 

 dark markings, especially on the under surface, whilst in the Palaearctic Region on the contrary the spring 

 form has more mai kings; ab. virginiensis Edw. (19 b) is distinguished from oleracea in that the forewing has virginlensis.^7 

 an indistinct dark apical spot on the upper surface and on the under surface of the hind'\^^ng there is very 

 fine but broad dark scaling along the veins, but specimens also occur in which the whole of the hindwing 

 beneath is darkened except for Hie fine white veins; such specimens have also broad grey streaks at the 

 veins at the apex of the forewing beneath; ab. pallida Scudd. is purer white above and beneath, only the pallida, ^j 

 $ has a small black spot on the upperside of the forewing. — The alpine and northern form bryoniae Oda;., bryoniae. ^^ 

 which occurs in Alaska as well as in some parts of the Palaearctic Region, has in the ? yellowish ground- 

 colour on the upper surface and rather broad dark margins to the veins. This form is considerabh' lighter 

 than the Palaearctic form of the same name. — acadia Edic. is a large form, which comes between pallida acadia.*^ 

 and biijoniae in colouring and pattern. — frigida Sntdd., from Labrador, is a whiter form and hulda Edic. frigida. 9^ 

 (19b). fi'om Alaska, is similar to frigida, but much smaller. - castoria Ueak. (= resedae Bdv), from Call- hulda. a^ 

 fornia, -is a form without much madving. — Larva brownish green, hghter at the sides, with small white <^a^tona.$^ 

 tubercles, black dots and a vellow lateral stripe, above which the black, red-yellow edged spiracles are placed, 

 head gi-ey-green: "29 — 30 mm. long, on the same plants as rapae. Pupa greenish yellow, with black spots 

 and dots and yellowish margin to the wing-cases. Egg pear-shaped, likewise laid singU'. 



P. protodice Bdt: (19 c), distributed from Canada to Guatemala, has white ground-colour, a \d,xge protodice. ^^ 

 median spot divided with white and in the cf slighter, in the ? stronger pattern of marginal and submarginal 

 spots on the forewing. The upper surface of the hindwing in the cf is almost without markings, in the ? with 

 submarginal dentate markings as w-ell as black marginal spots. The under surface has much paler markings 

 in hoth sexes. — In the winter form, vemalis Edu-., the rf* is smaller and less marked than the cf oi proto- vemalis.oS 

 fZ/c?, the 2 on the contrary scarcely different from that oi protodice. — Larva in the earlier stages unicolorous 

 orange-yellow, head black, in the later stages the head light straw-colour, posterior half light purple, a gold- 

 yellow spot on each side, the whole head sprinkled with black-brown, eyes purple, broadly edged with black. 

 Body alternately glossy gold-yellow and dark greenish purple, sometimes with unitorm, in other cases with 

 unequally broad black band. The yellow colouring of the sides of the back and of the stigraatal band runs 

 into the purple of the infrastigmatal band. Beneath dull light green w-ith reddish tinge. On the whole body 

 larger and smaller black spots, each of which bears a short black hair, also numerous small hairj^ tubercles 

 (from specimens preserved in glycerine). Pupa light bluish green, slightly suffused with yellowish on the 

 abdominal segments, a dull, broad yellowish lateral stripe on the abdomen, suprastigmatal ridges margined 

 with yellow. Head with small, dispersed blackish spots, wing-cases with faint dark brown marks, veius marked 

 with small, separated, distinct black spots, a black spot on the basal protuberance, segments of the antennae 

 mostly marked in the same way. The spiracles are the same colour as the body. Larva on Brassica oleracea, 

 Lepidium virginicum and other Crucifei's. 



P. occidentalis Beak. (19c), from the mountainous regions of the west of the United States, has the occidentalis. ^/ 

 dark markings more extended and less interrupted than protodice and the under surface, especiall}' of the 

 hindwing. is strongh' marked with green. — occideidaMs is regarded by Scudder as the third generation of 

 protedice (only occuiing in the west?). Thus it would seem that the early stages do not differ from those of 

 2irotodicf. 



P. sisymbrii IJdr. (19c), from the United States, is smaller than occidmtalis, the black marginal mark- sisymbrii.v/^ 

 ings are more sharply defined and divided by the veins, which are light here, but sharply dark in the rest 

 of the wings. The underside of the hindwing has black-green markings, broken up in a peculiar manner. 

 The $ is quite similar to the cf. — Egg long, narrow, conical, ground-surface and vertex flattened and 

 depressed, with longitudinal ridges, the interspaces hollowed out and crossed by numerous stripes; colouring 

 at first light yellow, shortly before emergence red. Full-grown larva about 22 mm. long, cyhndrical, moder- 

 ately narrowed anteriorly and posteriorly, light yellow, with black stripes crosswise, each segment sometimes 

 with a fold and in this case on the back small yellow protuberances of irregular size, each terminating in 

 a small fine hair: on aU the segments behind the 2. and inclusive of the 12. are 2 stripes. The larva varies 

 very much. Time of development from the egg to the pupa in April — May 33 days, in May — June 30 

 days. Pupa cylindrical, narrow at the head, hollowed out at the sides, a short thick projection between the 

 eyes, mesothorax projecting, rounded, slightly keeled in consequence of a depression as deep as the meso- 

 thorax is high, which however is not uniformly rounded but rather angular, on each side of the dorsum and 

 the anterior abdominal segments are small, angular, inconspicuous elevations, the anterior ones the most 

 distinct; colouring dark brown, the whole upperside except the wing-cases irregularly covered with small > 



protuberances (the pupa is figured by Edwards, Buttertlies of North America, hanging free). 



P. beckeri Edn\ (19 cj, from the United States, is similar to the £'mc/»/o '-species. Upper and under bcckcri. pf 

 surface white, on the upperside of the forewing a large black median spot, divided with white, and smaller 



