PIERIDAE. By H. Fruhstorfer. 
119 
2. Family: Pieridae, Whites. 
The greater part of the species of this cosmopolitan family live in South America and South Asia. The 
number of genera in the two regions is about the same. 
It is true that sharply defined species are rather more numerous in South America, but the Indian archi¬ 
pelagos produce an astonishing variety of local races, so that the two regions rival one another in a way which 
makes it difficult to decide where the maximum of development is to be sought. 
The large number of forms is due to local and climatic influences. The mightiest expanse of mountains 
in the world, the Himalayas with their off-shoots and the lowlands lying before them, are fully as favourable to 
the formation of species as the numerous islands in the Malay Archipelago. The highly diversified climatic con¬ 
ditions, partly caused by the regularity of the Monsoons and the consequent steady alternation of dry seasons 
and rainy periods, contribute further to the modification of species. 
Hence we meet both in the high-mountain species and in those of the plains and islands with unstable 
forms, often broken up into polychromatic and even polymorphic elements, the elucidation of which formerly 
occasioned serious difficulties. These forms have been described in the earlier works as an endless number of 
species, and to reduce them to their true status and to ascertain their geographical connection will be one of 
the principal objects of the following pages. 
But in spite of this extensive morphological variation all the Pierids have much in common; such as parti¬ 
cularly their very similar earlier stages and certain social habits. A noteworthy peculiarity of the Asiatic Pierids 
is their fondness for water, which is shown in their propensity for congregating on wet places in small or large 
numbers. They are frequently met with at river-banks or muddy places in such numbers that horses often shy 
when the Pierids rise up with an audible rustle. Sometimes they group themselves according to species so that 
the assemblages look like large flowers with white centres and gaily-coloured petals, or suggest large patches 
of snow, as I frequently observed in Siam. Most striking, however, is the peculiar migratory instinct of the 
Pierids. Appias and Catopsilia in particular follow an irresistible impulse and unite in swarms which travel even 
over mountains of 6000 ft., suspending their flight at sunset to resume it the next day with the same determination. 
I once observed such a flight in Java. On a sunny day, on the 13. January 1892, enormous swarms of Catopsilia 
began flying over Sukabumi in a westerly direction. These clouds of butterflies presented a wonderful spectacle, 
the flight lasting from 11 till towards 2 o’clock and the swarms appearing, as far as could be estimated, to be 
over 2 km. in breadth. The butterflies followed one another sometimes in large crowds, sometimes in groups 
at distances of from several inches to a few feet and at a height of about 4—6 m above the ground. On the 14. 
and 17. January similar flights were observed, but of shorter duration. The causes of the migration of such 
swarms have not yet been satisfactorily explained; the phenomenon observed by me was preceded by an unusually 
dry year, in which not a drop of rain had fallen in East Java for months, so that the consequent want of food 
perhaps furnished a motive for the emigration. 
Like the imagines the Pierid-larvae also often occur in such abundance as to become injurious, and are 
especially dangerous to young Ironwood trees (Cassia florida L.). Grass and low bushes in the neighbourhood 
of these plantations are then covered with the pupae, from which the butterflies emerge in January, in such 
numbers as to fill the air as if with white snow-flakes (Martin). 
The eggs of the Indian Pierids are spindle-shaped, being sometimes very wide, so that they look like 
soda-water bottles, twice as high as broad, with longitudinal ribs, which are connected by fine transverse ridges. 
Towards the apex they are sometimes produced into a short point. The colour principally white, variable, some¬ 
times becoming yellow and orange. The eggs of Hupliina are spotted with red and those of Leptosia are whitish 
to quite blue. The eggs are as a rule laid singly on the upperside of a leaf or on young shoots. Exceptions are 
Colotis amata F., Appias hippoicles Moore, Delias eucharis Don., Anaphais mesentina Cr. and Terias silhetana Wall.. 
whose eggs are deposited in clusters. The larvae of these species live gregariosly in the first stages, but separate 
when they are well grown if they find sufficient food. 
The larvae of the Asiatic species, when adult, lie on the upperside of a leaf and, when they live isolated, 
along the midrib, where they cover the leaf with a silver web. Some are said to have carniverous tendencies, 
