54 PIERIDAE. By J. Robee. 



Sexual dimorphism is well developed in manj- species from all the faunistic regions, seasonal dimor- 

 phism naturally onlj^ in those species which inhabit districts with sharply marked seasonal changes. 



Antennae of varj'ing lengths, e. g. in Lepfidia rather short, in the South American genus Lepto- 

 phobia on the contrarj^ verj- long, the club clearly defined or gradually thickened. Forelegs normally deve- 

 loped, therefore capable of use, with bifid claws. Proboscis well developed. The butterflies feed at flowers 

 and moist places on the ground. Palpi well developed, but variable. Male secondary sexual characters 

 (seent-organs) occur in the species of several genera, e. g. in Co/ias as a specialty scaled spot on the hindwing, 

 in CatopsiJia as broad patches of thick scaling, in Appias (Tachi/ris) as a pencil on the underside of the ab- 

 domen, in Dismorphia as large chalk}' spots of scales on the under surface of the forewing, from which the 

 scent is given off h\ rubbing against the strongly widened anterior part of the hindwing. Other species 

 (e. g. Pieris brassicae and its allies) possess feather-brush scales (Aurivillius) , which are extended over the 

 greater part of the wing and apparently are the cause of the suppression of the dark markings in the cfcf, 

 and other species again (e. g. Pieris buniae from South America) broad stripes of thick chalky scales along 

 the veins. 



The Pierids — like most Rliopalocera — are sun-loving insects, but, m common with a few other 

 butterflies (mosth" Satyrids), nevertheless extend into the Arctic, Antarctic and Alpine regions, without losing 

 anything in brilliancy of colouring in comparison with allied genera from warmer districts. The high moun- 

 tains of South America and the south-eastern boundar}- of the Palaearctic Region each even possess two 

 genera quite pecuhar to themselves, namely the former Phidia with about six species and Andina with 

 one Colias-like species, and the latter Mesapia and BaJtia, of which the last-named is Yevy nearly allied 

 to Phulia. 



The Pierids are as a rule moderate fliers, but some also fly unusually swiftl}' (Appias) and others 

 so slowly that they can be caught with the hand when on the whig (Leucidia). Thej' occur in one or 

 more generations. 



The intellect is obviouslj- very different in the various Pierids, for whilst for mstance Pieris brassicae 

 and the CoZ/as-species are capable of very quickly recognising danger when pursued by the collector, this 

 is much less to be observed in others (Pieris napi and rapae). 



The swarming and migration of the butterflies, already referred to, have been regarded as nuptial 

 flights; GatopsiUas and Pieris brassicae especially have been observed to form such swarms. 



The eggs are oblong, are laid in an upright position singly or in clusters, sometimes in large nium- 

 bers, on the underside of the leaves of the food-plant, and are of different colours. 



The larvae are cylindrical, mostly of green or gi-eeuish ground-colour with light longitudinal stripes 

 and short hairs; none have yet been observed with spiny or such like processes. Thej' do not possess the 

 fork on the neck characteristic of the Papilionid larvae, which is said to afford the insects protection from 

 their enemies bj^ the emission of an unpleasant odour, neither has it been proved that — like many Papi- 

 lionid larvae — they acquire poisonous or at least nauseous properties from their food; nevertheless they 

 are not only unpalatable to birds, but is has also been observed that fowls which had been fed on these 

 larvae died, evidenth' in consequence of a poison contained in their bodies. They live on various shrubs 

 and herbaceous plants, such as Papilionaceae, Mimosas, Crucifers and Caparideae. 



The pupa is attached to plants etc., by its abdomen, in an upright or hanging position, and is held 

 in this position bj^ a girth. Some are of very singular form, such as the tube-shaped pupae of the species 

 of Anthocharis ; but in general the Pierid pupae show few differences. The Palaearctic Zegris euplieme — 

 and probably not only the other Palaearctic species (Z. faiisfi), but also the Xorth American Z. oli/nqna — 

 pupates in a rather thick cocoon, but still possesses a remnant of the girth. This characteristic (recalling the 

 »Bombj'cids«) is much more pronounced in the ilexican Euclieira socialis. The larvae of this species are 

 gregarious and go out at night in a procession to feed. The common web hangs down from a bough, in 

 the form of a pouch; the pupae are fastened in it head downwards (J. Alemax). 



Some of the Pierids hibernate as pupae, some as larvae, and some — e. g. the Palaearctic Gonep- 

 /ery.r-species — as butterflies. 



In the Palaeartic and Nearctic Regions the Pierids preponderate by their great number of indivi- 

 duals, in the tropics they are more restricted. Some Pierids have a verj' extensive range, thus Pieris rapae 

 and napi occur in the whole Palaearctic and the Nearctic Regions, Belenois mesentina in the southern 

 Palaearctic, Indian and African Regions. 



Although — as already mentioned — the larvae do not appear to absorb poison from their food- 

 plants, the butterflies are very Uttle pursued bj" the birds, and are therefore apparently unpalatable to them 

 or at least not much appreciated. 



Several fossil Pierids have been found, which do not differ in size from the present-daj- species. 



