820 



ARTHROPODA phylum vii 



Order 2. CAMPODBOIDEA Handlirsch {Archinseda Haeckel). 



Siiudl Ajilerinii'ir i nfnlvitphovs hisects {mouih parts or trophi reduced and huried in 

 fite had) vith f>'elilij~(h'n loi^'d njrt; and long, simple, midtiarticulate antennae. Bodtj 

 Segments very nearly eqttal ; ten well-developed abdominal segments, most of them with 

 reduced styliform legs ; cerci elongate or chelate. 



The so-called abdominal legs in tliis gronp and in the Thysanura are appendages 

 ^vlli(•ll help to support tlie abdoraen, and serve also as tactile organs. They are 

 ciillcil by Grassi false legs or '' Pseiidoza7npe" The Recent genus Campodea Westwood 

 occurs also in Baltic aniber of LoAver Oligocene age. 



Order 3. COLLEMBOLA Lubbock. (Spring-tails). 



Trophi reduced and huried in the head, eyes feehly developed, antennae sometimes 

 unequally segmented. Thorax with very unequal segments hut with homonomous legs. 

 Abdomen consisting of not more than six segments, the first of ivhich is furnished with a 

 ventral tuhe or papilla, and modified legs forming a springing apparatus being present 

 posteriorly. 



About 450 Recent species of Spring-tails are known, and 70 have been recorded 

 fi'oni Baltic amber of Lower Oligocene age. The crustacean characters which we 

 find to-day in the CoUembola, the Thysanura, and tlie Ephemerida, are, as pointed 

 out by G. H, Carpenter, without doubt inherited survivals, indicating a true relation- 

 ship between the two subphyla of Branchiata and Insecta. 



Order 4. PROTURA Silvestri (Myrientoma Berlese). 

 Minute subterraneous Insects without antennae and eyes. 

 This Order is without known representatives in the fossil State. 



Geological Range and Distribution of Insecta. 



It is estimated that about 1000 Paleozoic, as many Mesozoic, and upwards of 

 8000 Cenozoic Insects have been described by different authors. The total is, 

 however, a mere fragment of the insect fauna of past periods, and very small in 

 comparison with the half million species now in existence. 



The earliest fossil Insects which have been definitely recognised are members of 

 the Palaeodictyoptera. Their first appearance in Europe is at the base of the Upper 

 Productive Goal Measures (Ouralien or Stephanien superienre of Commentry, France, 

 and the corresponding 'umteres Obercarbon" of German geologists). From the 

 Upper Goal Measures of France, Germany, Belgium, Bohemia, and other localities in 

 l^urope, and Irom the Lower Productive Goal Measures (Kanawha and Alleglieny 

 ormations) of Pennsylvania, Illinois and elsewhere in the United States and Canada 

 has been obtamed a large number of highly interesting types.i Other- representatives 



renilinrwil^fnf ""'1^'''''^ ""! ^^- '^°^"' ^^^- B^^ii^wick, which has yielded a number of insect 

 PaeobotaiTv tnn?rT^ regarded as of Devonian age, but is now assigned on the evidence of 

 (livisbro7t ./pn^^^ ^"^^ ^'"^^^^^' corresponding to the Kanawha Group (upper 



pZZI .^.It f '^/n^P^^'^^^ ''''''^ '''''S, described by Moberg under the !>ame of 

 Anot r^oub ful f; "^ the Graptohte beds of Sweden is probably not of Arthropod nature. 

 M^^Surit ofr.,^^^^^^^^ '\' '°-'""^^ ^'^^^^oUattina douvül J of Brongniartf from the 

 S f^e l^^^^^^ T Hl erpreted by Agnus as part of the pleural lobe of a Trilobite. 



irMiiS^sTlns..?. , . '\\"'^n' ?«^""ianrocksof the south-east of Ireland, but no indubitable 



fouu.l .t Fnrnl.v r- i'.'"', <-=irboniferous have been as yet forthcoming. Tlie insect remains 



f-i,. th.. Fkr ia.it 1 p'l ',"■' ""'"^ ^^'°"^^* *" ^'' ^f ^''"^'^'' ^««tead of Triassic age. Those 

 fonue.lv '^' ^''' "°'' ^■^*"^"-«*^ to the Miocene, instead of to the Oligocene, "" 



11 e, f^s^^M 



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