80 LEUGIDIA; TERIAS. By J. Robee. 



18. Genus: Tjeucidia iJhl. 



This genus contains the smallest torms of Pierids and is confined to tropical America, for the state- 

 ment that one species {impura Voll) also occurs on Timor in the Indian Ocean is undoubtedly incor- 

 rect. The Leucidias have an extremely weak flight, for they fl}' so slowly that they can be caught with the 

 hand in the air. The cause of this want of swiftness in flight lies probably (apart from the weakness of the 

 body) in the form of the wings; the forewing is so very much rounded that it can hardlj' be said to have 

 an apical angle. In structure this genus is more nearly allied with the superficially similar Ponlia from India 

 and Africa. The antennae are scaled along the whole length and gradually thickened to a small club. The 

 subcostal is four-branched, the first branch arising far before the end of the cell and the second soon after it, 

 the third and fourth branches form a short fork. The upper radial anastomoses to the half with the sub- 

 costal, consequently the upper discocellular is wanting. The hindwing has an almost straight costal margin, 

 only very weakly emarginate, the simple precostal is curved proximally and the subcostal and upper radial 

 have a common stalk. It is doubtful whether the forms erected as separate species are really independent 

 or onl}" forms of one or two species. 



/'" ■■ hrephos. L. brephos Hbn. (= leucoma Bates?) (24 f), occurring from Venezuela to South Brazil (Sao Paulo), 



is Avhite with a very slight j-ellowish tone, sometimes there is a fine blackish line at the anterior part of the 

 forewing. The under surface is white. 



lt>^ pygmaea. L. pygmaea Frittu: (241'), from Brazil (Rio de Janeiro, Sao Paulo, etc.), is above and beneath yel- 



lowish white with narrow blackish distal margin on the upperside of the forewing. 



It lb exigua. L. exigua Prifttc. (241), from Venezuela and the Brazilian province of Rio de Janeiro (Gorcovado 



and Leopoldina) is larger, yellow, and has a considerably broader black distal margin on the forewing, 

 which extends to the inner angle. 



A^y elvina. L. elvlna God'. Q= impura Voll.) (24 f;, from Brazil (e. g. Sao Paulo), has shghtly yellowish white 



' upper surface and more strongly yellowish under surface, with rather broad black distal margin of the fore- 



wing above. My specimens of this species completely agree with the description and figures of impura, said 

 to be indigenous to Timor. 



19. Genus: Terias Suai>is. 



This genus , which in the eastern hemisphere onl}^ extends a little . beyond the tropics, occurs in 

 America much further north, a few species advancing as far as the southern boundary of Canada. Though 

 the Terias are mostly only small species, their richness both in species and individuals makes them quite 

 a feature of the fauna. Their agilitj- varies considerabl}'; whilst the species with the apex of the forewing 

 pointed (e. g. r/tincllacliia) are good fliers, the round-winged species (e. g. albula) scarcely surpass Leucidia. 

 With this genus begins the series of those Pierids which E. Schatz includes under the general name of 

 "Dryads"; these are Pierids with the antennae sliort, strong, mostlj' without clubs, only gradually thickened 

 towards the end and but rarely having a distinctly formed club. The species of Tevias are mostly small, 

 only exceptionally medium-sized, yellow or orange-coloured butterflies. The head is retracted; the eyes are 

 naked and very little prominent, the palpi moderately long and laterally compressed, with large basal joint 

 and small pointed terminal joint. The antennae are delicate, with gradually thickened, more or less distinct 

 club. The subcostal is four-branched, with two branches before the end of the cell, the upper radial is 

 partly coincident with the subcostal, consequenth* the upper discocellular is wanting. The hindwing is rounded 

 or bears a short tail. On the position of the upper radial of the hindwing Bltler has based the genera 

 Sljhaenogona (with ectriva Dbl. as type) and Pijrisitia (with proterpia F. as type). The origin of this vein is 

 however rather variable: it either ariseo from the cell or at the origin of the subcostal or it has a common 

 stalk with the latter. But as all sorts of transitions occur between these positions, the position of the upper 

 radial is of no use as a generic character. — The larvae are slender, with short, soft hairs and mostly 

 green. The pupae are somewhat curved, weakly compressed laterallj', keeled on the dorsum, without lateral 

 spines and narrowed to a point anteriorly. — The species of Terias prefer open situations with low shrubs 

 and moist places, on which they often appear in large numbers, sometimes they congregate in great crowds, 

 which often traverse long distances, even over the sea. They probabh' occur without exception in at least 

 two generations, which are sometimes ver}' different superficiallj-, but the identit}' of the seasonal forms has 

 onl}- been proved in very few exotic species. Doubtless they have likewise developed local forms, but con- 

 cerning this also very little is known with certainty. — A large number of rer/fts-species have been erected 

 which very probablj' might be united with those dealt with below. In many cases mere individuals, and 

 often also scarcely tenable local forms have been described as separate species. We cannot here go into 

 the classification of all these unimportant forms, that would rather be a task for a monographic work on 

 the genus. For the large African Region Chr. Aueivillics onlj- accepts eight species (including two doubtful 

 ones). As in the following pages 43 species in 86 forms are dealt with, no principal form at any rate will 

 be left unnoticed. 



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