394 NEW YORK STATE MUSEUAI 



be found likewise to differ. It has an abundance of dragon flies and 

 caddis flies and of certain Diptera, while certain other groups, notably 

 the stone flies, which require more rapid and rocky streams, are not well 

 represented. 



Place of insects in natural societies. A very little was done by 

 us in the study of this subject, but that little constitutes part 2 of the 

 present report. 



Reproductive capacity of insects. But one thing was attempted 

 under this head, and that was the determination of the number of eggs 

 laid by individuals of a number of species, by means of the examination 

 of the ovaries of newly transformed females. This undertaking at once 

 revealed some interesting biologic facts, which might, perhaps, have been 

 inferred in advance, and which may be known, though I have not read 

 of them. These may be stated as follows. 



1 In certain insects (as May flies, caddis flies, gnats, etc.) which 

 lack functional mouth parts, and whose adult life is very brief, the eggs 

 are well developed at transformation, and may readily be counted, the 

 difference in size between the developed eggs and the egg rudiments 

 which will not develop being very marked. 



2 In other insects (such as the larger dragon flies) the eggs are very 

 immature at transformation, and it is impossible to determine how many 

 of the egg rudiments present at that time will develop into eggs. In 

 other words, the time of the maturing of the eggs is related to the dura- 

 tion of the adult life, and to the amount of food taken during adult life. 



Having read that the larger dragon flies of the gomphine group live as 

 imagos but a week, I was surprised to find that the eggs of a newly 

 transformed female of Hagenius brevistylus were so immature 

 as to be scarcely recognizable ; but I have since observed that there is 

 in this and in many other large gomphine species an interval of about a 

 month between the period of transformation and that of oviposition. I 

 am inclined to think that the dragon flies which have been kept success- 

 fully only a week in confinement have died of starvation, aiid that in 

 any case the length of imaginal life is not fairly determined so. 



The few counts successfully made by us from insect ovaries will be 

 found under the discussion of the species on which they were made. 



Study of the habits of insects. What animals do has always 

 been an interesting subject of inquiry, and probably will always be 

 so. A knowledge of the habits of animals has its own peculiar cul- 

 ture value, now generally recognized. It has a higher scientific value, 



