PREFACE. 
The present part of the ' Illustrations ' is p faunistic monograph, containing a systematic 
list of all the Lepidoptera Heterocera hitherto recorded from the Nilgiri district of S. India, 
and descriptions and figures of the numerous new species in the collection in the British 
Museum. It has been prepared by Mr. G. F. Hampson, who has kindly supplied me witli 
the following particulars as regards the physical features of this district : — 
"The Nilgiri district consists of a wedge-shaped spur of mountains, with a base of 30 
miles, and an extreme length of 60 miles, running out from the Western Ghats and forming 
the commencement of the Eastern Ghats. The plains at the foot of the hills have an average 
temperature of some 80° F., whilst the plateau, with a mean temperature of but little over 
60" F., is subject to sharp frosts in December and January ; its elevation is from 6000 to 
7000 feet, peaks running up to nearly 9000 feet : from the plateau precipitous slopes descend 
on the west to the plains of Malabar, but little above sea-level ; on the south to the Palghat 
Gap, 1000 feet ; and on the north to the Mysore plateau, 3000 feet. The western slopes 
forming part of the face of the Ghats get a rainfall of 300 inches, while on the lower slopes 
at the eastern end the rainfall does not exceed 30 inches, so that the most diverse conditions 
obtain ; consequently, while the Western slopes have a tropical Ceylonese fauna, the Eastern 
have that characteristic of the arid plains of India; whilst on the plateau many outlying 
members of the Palsearctic fauna occur." 
The materials on which this Monograph has been based are as follows : — 1. A collection 
of about 1000 species made by the Author in various parts of the district during the year 
1888 and now transferred to the British Museum ; to each specimen of this collection the 
