170 INSECT BEHAVIOR 



in some cases with microscopic lavender scales like those of a fish. 

 Those belonging to the Thysanura possess strange forked appendages 

 which protrude like long tails from the posterior segments of the 

 body. These are in addition to the legs, and antennae or feelers, and 

 their purpose is not definitely known. 



In Collembola the species are supplied with a catch, and spring, 

 which upon release, hurls the creature bodily and automatically out 

 of harm's way. They are also supplied with paired sacs, which are 

 carried upon the ventral tube of the first of the six body segments. 

 These assist the creature when walking upon very smooth surfaces 

 and doubtless serve as breathing organs in addition. 



As it is extremely unlikely that such delicate insects could be 

 transported across seas and oceans, their remarkable geographical 

 range, so wide and discontinuous, suggests their great antiquity. 

 Doubtless in ages past, before our planet was in the process of change 

 towards what it is today, there were no seas or channels separating 

 the various countries included in the range of the Aptera. The 

 United States and Europe, together with Chile and the more 

 isolated islands, were probably one continuous continent. If not,' 

 why then should we find these identical little insects in each of those 

 places today? That they are of very ancient origin is undoubted. 

 It is what makes the Aptera so important and interesting to scientists 

 today. 



Geologists have found many fossil remains of these insects in very 

 ancient strata of the earth's crust. A supposed specimen was 

 unearthed from the Silurian deposits of New Brunswick, buried 

 there during a comparatively quiescent period in the earth's history. 

 At this time a great sinking of the land was followed by a relative 

 rising, which affected wide areas in the northern hemisphere. Other 

 remains found in Carboniferous deposits in France were of Aptera 

 which lived in prehistoric forests of great exuberance, before they 



