PREFACE. 



The present part of the ' Illustrations ' is a faunistic monograph, containing a systematic 

 list o£ 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 with 

 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 tlie south to the Palghat 

 Gap, 1000 feet ; and on the north to tlie jNIysore 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 e.Kceed 30 inches, so that the most diverse conditions 

 obtain; consequently, while the Western slopes have a tropical Ceylouese fauna, the Eastern 

 have that characteristic of the arid plains of India ; wliilst on the plateau many outlying 

 members of the Palaearctic 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 



