Page four 



EVOLUTION 



February, 1931 



If, however, the technique of measurement and understand- 

 ing ahvays involves hght of the wave lengths and properties we 

 know about, a displacement of the observer from the middle of 

 the scale does not help in penetrating the cosmos. Bacterium or 

 Betelegeusian — he finds that the tools, not the vision, set the 

 limits, or at least constitute the handicap. New tools are needed, 

 not a dimensional displacement of the observer. 



Our pivotal position in the scale of dimensions is probably 

 just another of the grim illusions that make man appear to be 

 importantly in the midst of the measureable world. As with his 

 once flourishing geocentrism, further research may again easily 

 decentralize him. We can attach no cosmic significance to his 

 position in the universe. We are, as remarked above, indulging 

 vain fancy . . . 



Comprehensive and final, the word Universe seems most ob- 

 vious for the name of our ultimate class ... In our present 

 usage, the Universe includes every material thing we know. Is 

 it not natural and appropriate therefore to terminate the survey 

 at this point, with the classes running from — 4, Corpuscles, to 

 + 12, The Universe? 



If a hundred years ago we had surveyed the systems within 

 the universe as then comprehended, it is certain that at both 

 ends the list of recognized material systems would have been 

 more limited. Atoms were not treated as systems, but as units. 

 Electrons were unknown. In the macrocosmos there were vague- 

 ly understood galaxies, but nothing higher was definitely visu- 

 alized. Very little was accurately known, of course, concern- 

 ing sidereal distances or stellar population. The warning of 

 scientific history is certainly that our growing knowledge of 

 The Universe may soon cross present boundaries, and that we 



should allow for systems beyond those now conceived. Scien- 

 tific pronouncements concerning unsurpassable limits in dimen- 

 sions and masses or ultimates in organization are likely to be 

 mere dogma. 



I suggest, therefore, that Class +13 . . . be set up, partly 

 as a matter of safety, partly as a challenge. 



Numbers of Particles 



Hydrogen atom 2 



Mercury atom 400 



One gram lo''^ 



Comet 10" 



Earth lo" 



Sun lO" 



Globular Cluster lo" 



Galaxy 10 



Supergalaxy 10 



The Universe >10"(?) 



Diameters of Material Systems 



cm 



Proton 10"" 



Atom 10-* 



Molecule 10"' 



Colloid 10-° 



Comet and Meteor Stream lo' 



Earth-moon System lo" 



Solar System lo'* 



Galactic Cluster lo" 



Globular Cluster 10™ 



Star cloud and Galaxy lo" 



The Galactic System 10^' 



The Metagalaxy ^ 10^' 



The Universe (radius) lO^'C?) 



Evolution of Insects 



By F. M. CARPENTER 



' I 'HE insects occupy the same position among the inverte- 

 •^ brates that the birds do among the vertebrates: they are 

 the sole members of their respective series to develop true 

 wings. But the insects have undergone more changes in struc- 

 ture in adaptation to their surroundings and modes of living 

 than any other animal forms. Most of them are winged and 

 strong fliers; many possess oar-like legs and swim in lakes and 

 streams; others have legs shaped like shovels and live in the 

 soil; and a few others have lost all appendages and live within 

 the body of some animal, feeding on the tissues and body 

 fluids. Such a diversity of structure is an indication of great 

 age and implies that much modification or evolution has taken 

 place within the group. 



From numerous investigations on fossil insects it is certain 

 that as far back as the middle Tertiary period (about fifty 

 milUon years ago) the insects had already reached a develop- 

 ment as specialized as that of the living species. Most of the 

 genera, or species-groups, of the Tertiary are still existing. It 

 is interesting to find that nearly all these genera once lived in 

 different regions of the earth than they do now. The Tse-tse 

 fly (Glossina), which carries the dreaded African "sleeping 

 sickness," now restricted to the Old World tropics, inhabited 

 the Colorado region during the mid-Tertiary. 



If we go back to the middle Mesozoic (about 150 million 

 years ago) , we find a stranger assortment of insects; some of 

 the existing families were present, but most of the species were 

 less complex in structure than the modern or Teritary ones. 



When we go back to the Permian period (about 200 million 

 years) , we can find no living families, although there are sev- 

 eral familiar orders, the cockroaches, dragon-flies, scorpion-flies 

 and such primitive types. The Permian insects, however, were 

 more primitive in most respects than their existing relatives. 



Now if we turn over another page of our geological calendar, 

 we come to the Upper Carboniferous (about 250 million 

 years) , in which the first insects are found. Only in the top 

 layers of these strata do we find an existing group of insects, 

 — the cockroaches; all the other species, especially those of the 

 lower beds, belong to orders which have long since become ex- 

 tinct. They possessed none of the modifications or specializa- 

 tions which characterize our modern forms. The three seg- 

 ments of the thorax were equal in size and shape, showing no 

 differentiation; whereas in living insects the two segments which 

 bear the wings have become enlarged by, or for, the expansion 

 of the muscles within. In other groups of recent insects, such 

 as the leaf -hoppers, the first segment of the thorax possesses 

 elaborate spines or some other form of armature. 



