22 
INTRODUCTION. 
In addition to this, which is true of nearly every family of insects, there 
are families which are confined to the subtropical region, or which im¬ 
mensely predominate there as compared with these families in the 
plains, and there are also families which occur far more abundantly in 
the tropical plains. The Phasmidce , Siricidce , Tenthredinidce , Sialidce, 
Panorpidce, Passalidce, Lucanidce, Simuliidce, Aradidce , Phymatidce, 
Sesiidce , Zygcenidce are practically confined to the moist forested lower hill 
slopes; the Rhopalocera are characteristic of the subtropical region, 
especially the Nymphalidce and Papilionidce ; the Cicadidce, Tipulidce , 
Mycetophilidce, Locustidce , Dynast idee. Cetoniidce , Erotylidce , Endomychidce, 
Boslrichidce, Scolytidce are found abundantly in the subtropical, rarely 
in the tropical areas ; Chrysomelidce, Buprestidce, Capsidce. Syrphidce 
occur in both but in immense profusion only in the former ; Limacodidce 
and Pliryganeidoe stand out conspicuously in the same way. On the 
other hand, the Acridiidce, Carabidce , Dytiscidce , Hydrophilidce, Gyrinidce, 
Tenebrionidce, Myrmeleonince , Ascalaphince , Scaraboeidce are far more 
abundant in the plains, though occurring also in the lower hills. Allow¬ 
ing for the fundamental excess of species in the subtropical region owing 
to its varied flora, the other large families are more proportionately 
represented in both areas. We would suggest also that the varied sur¬ 
face fauna of the plains is less marked a feature of the subtropical region, 
possibly because the surface soil offers protection from heat not required 
in the hills and because the usually dense perpetual vegetation of 
the hills produces a fauna centering more round the bushes and low 
vegetation (see below u Where Insects Live ” under Forficulidce). 
This fundamental distinction is of the very greatest importance, and 
unless it is fully realised and clearly kept in mind, any conception of the 
faunal zones must be imperfect. We sharply mark off the fauna of the 
plains of India (usually below 2,000 feet) from that of the forested 
slopes of the hills and from that of the upper hills; and, in this 
volume, we deal only with the tropical zone except where the number 
of species occurring in India is stated when we mean British India 
exclusive of the temperate upper Himalayas. 
India is placed by Beddard (Zoogeography 1895) in the Oriental 
Region as the “ Indian ” subregion ; Ceylon is distinct as a subregion and 
is taken to include part of South India. The Himalayas, inclusive of 
Kashmir, Nepal, Sikkim, Bhutan, are not part of the Indian subregion 
