' INSECT PLAGUES OP THE SIKKIM 93 



The insects, however, and other invertebrata, make up by 



' their numbers for the absence of warm-blooded animals, and 



are often insupportable plagues to the wanderer. Beautiful 



, tropical butterflies sometimes ascend to heights of 10,000 feet, 



i along with the less agreeable mosquitos and ticks ; and in all 



the streams, up to an elevation of 7000 feet, hill-leeches occur in 



such multitudes that bathing is almost impossible. 



