Apeil 30, 1897.] 



SCIENCE. 



671 



On such occasions, and, indeed, on all 

 occasions when the Academy is in session 

 for other than the transaction of its private 

 business, the presence of a goodly number 

 of its members would be desirable, and it 

 ought not to forget that it is a National 

 Academy, chartered by the government; 

 therefore to a degree the creature of the 

 people and their representatives in the 

 highest domain of scientific investigation. 

 Thej' do not wish to direct or restrict its 

 operations, but are content to see that they 

 are controlled by a membership which in- 

 cludes the ablest specialists which the 

 country produces, selected from time to 

 time in accordance with a standard with 

 which they have no particular quarrel. 

 On the other hand, the Academy may well 

 give great consideration to its obligations 

 to such an enormous and unusually intelli- 

 gent constituency, whose character and 

 dignity, from the scientific standpoint, it is 

 delegated to represent. 



The November meeting will be this year 

 in Boston, beginning on Tuesday, the six- 

 teenth of that month. 



AN ESSAY ON THE CLASSIFICATION OF 

 INSECTS. 

 Of late years the phylogeny of insects 

 has attracted considerable attention from 

 students, and much light has been thrown 

 upon the subject by the researches made. 

 One of the most notable facts has been the 

 breaking away from the old Linnsean orders 

 and the substitution of a number of more 

 compact assemblages for some of the almost 

 indefinable aggregations found in the old 

 classification. New characters have been 

 sought, not only in structures visible exter- 

 nally, but even in internal anatomical pe- 

 culiarities. The subject is a very interest- 

 ing one, which the teacher is of necessity 

 compelled to study more or less, and which I 

 was led to examine more particularly when 

 the question recently came up as to the adop- 



tion of some system in a general work on 

 ' Economic Entomology,' which has since 

 been published. The conclusions reached 

 by myself, while in general they agree with 

 the latest published results, have been ar- 

 rived at by a somewhat different method, 

 and my ideas concerning the development 

 of the orders are somewhat unlike those 

 heretofore accepted. I have tried to ad- 

 here logically to a scheme of easy develop- 

 ment, and have made use of some charac- 

 ters not heretofore particularly noted. 

 Leaving aside for the present all questions 

 as to the origin of the class ' Insecta ' and 

 as to its ancestors, I start from a developed 

 hexapod — an archetypal Thysanuran with 

 six, jointed legs ; without wings ; with or 

 without abdominal appendages other than 

 functional legs ; with no eyes or with ocelli 

 only ; with a head not greatly diifering in 

 size or form from the body segments ; with 

 the thoracic segments equally developed 

 and not greatly differing except in append- 

 ages from those of the abdomen. This 

 creature lived in moist places, perhaps par- 

 tially in the water, and had the tracheal 

 system feebly or not at all developed ; 

 absorbing oxygen chiefly through the skin 

 and tending, perhaps, as much in the di- 

 rection of an aquatic as a terrestrial life. It 

 had no distinct metamorphosis, was ovip- 

 arous, bisexed, changing little in appear- 

 ance from the time it emerged from the egg 

 until it was adult and capable of reproduc- 

 tion. The mouth structures were general- 

 ized, feebly developed ; but with at least 

 three, and possibly four, pairs of composite 

 structures corresponding to mandibles, 

 maxillee and labium of our existing insects. 

 The possible fourth pair may have been an 

 endo-labium and, pei-haps, the labrum with 

 its attached epipharynx may have required 

 a fifth pair of structures. Most essential of 

 all was an inherent power of variation and 

 adaptation, and probably, as with some of 

 our present Thysanurans, reproduction was 



