OF WASHINGTON. 117 



characterizations of genera, particularly in the groups of the 

 smaller species, and especially when we remember that the dis 

 coveries of every year cause constant revision of previous studies 

 in both of these particulars. 



The vastness of the field of entomology is indicated by the fore 

 going figures, and that the field is practically inexhaustible from 

 the present standpoint seems to be also fully demonstrated. 



Present Rate of Description, and Probable Time of Com 

 pletion of the Work. 



It is an interesting problem to determine how many years more 

 it will take to describe the insects of the world at the present rate 

 of progress. The activity in collecting and describing insects has 

 never been greater than at the present time, and the number of 

 workers is being increased yearly ; but as the more accessible 

 regions of the world are worked over, the securing of new species 

 will become more and more difficult and it is reasonable to sup 

 pose that even with the constant increase in the number of 

 students of insects the rate of description of new species will 

 probably never very much exceed the present. 



Taking the Zoological Record as a basis for computation (and 

 the records therein given are not at all complete), it appears that 

 during the last few years there has been an average of i ,000 new 

 genera and subgenera of insects described yearly, not including 

 the Arachnids and Myriapods, which would add 200 additional 

 genera. This makes a total of 1,200 new genera yearly out of a 

 total for all animals (that is, including insects) of some 1,700 

 genera. The number of new genera added yearly is somewhat 

 astonishing when it is remembered that Linn had altogether but 

 74 genera of insects. Some ten years since, Dr. Sharp estimated 

 that during the last 120 years, or since the time of Linne, an 

 average of about 2,000 new species of insects had been annually 

 described. Taking the results of the more recent years as a 

 basis, Lord Walsingham has estimated the number of species now 

 described yearly at 5,000. This is after deducting 8 per cent, 

 for possible synonyms and is considerably below the annual 

 increase indicated for the last 36 years in our recent quotations from 



