146 Indian Museum Notes. [ Vol. II. 



any very large extent in India, it is certain to be very deficient in 

 the list of orops and otlier products which these pesfs attack. This 

 defect is being gradually remedied as information accumulates, but 

 progress is necessarily slow. 



The habits of many of the insects that are recorded in this conspectus 

 Extent to which the habits have been more or less completely traced, in 

 of the insects are known. India, and the number of such species is con- 



stantly incre:isii)g. With regard to the remainder, although little lias 

 been done in observing them in India, yet, in the great majority of cases, 

 a good deal is known iis to the main features of their habits; for almost 

 all of them are allied to. and some of them are actually identical with, 

 species which have been kept under observation in other parts of the 

 world. It is true that in some instances closely allied species are found 

 to have ver3' different liabits, but the cases where this is likely to happen 

 are fairly well known, so that upon the whole it does not seriously in- 

 terfere with the reliability of the deductions that can be drawn from the 

 work that has been done elsewhere. 



With regard to the relative importance of the insects that have been 

 included, some of them (e.g., the mosquito 



Their relative importance. 7,- 7, ,. , ,, ,„ 7 1 , 



bligkt or tea, the coffee borer and green bug 

 of coffee, the cub worms, sapper, and hispa of rice, the hover of 

 sugarcane, and the iveevil of wheat) are known to do grtat damage in 

 India; these are printed in capital letters to distinguish them from the 

 majority of the species which, though they attack crops and are always 

 liable to increase so as to do serious damage, are not actually known to 

 have done so as yet. As information accumulates, many of the insects 

 at present only recorded as occurring on crops will no doulit have to be 

 transferred to the ranks of those wliich are known to do serious damage, 

 while it will be possible to weed out others to form a third division of 

 such insects as attack crops but are of no economic importance. In tlie 

 present stage of the investigation the division of the insests, which are 

 known to attack crops in India, into two groups, is all that can profit- 

 ably be attempted. 



The difficulty in identifying insects is ver3'' great, for there are at 

 The difficulty in identifying least twenty thousand different kinds of 

 species. insects in India already described, besides 



a vast number of mit:ute species which have hitherto been very much 

 neglected by entomologists; though many of Ihem are of great import- 

 ance economically. Each of these insects passes through several 

 stages of grovvth,"whieh generally have no more resemblance to each 

 other than the silk worm has to the moth into which it changes. Again, 

 in the great majority of cases, the injury to the crops is done by 

 immature insects. Now, the immature forms of different insects are 



