( i VSSIFH \ i 



The following diagram I i udely one 



In tin- annelid origin of tin- i hid < lasses of Art liropo<l;i . 



Tin- naturalness of the phylum Art hn.poda WAI questioned by 

 Icy .ind I'aikard. The lath-r author divided Art hro|>o<lii into 

 live independent phyla, holding that "th( no common ancestor 



of tin- Arthropoda as a \\ hole, and that the group i> a polyphyleti< one/' 

 This LCOnodastic view, however, hy emphasi/.ing unduly the -tnntural 

 differences among arthropod^ tends to conceal the 

 many deep seated resemblances that exir-t between the 

 dasses of Arthropoda. 



Carpenter, in a most sagacious summary of the 

 whole subject of arthropod relationships, brought to- 

 gether no little evidence in favor of a revised form of 

 the old Mullerian theory of crustacean origins. He 

 traced all the classes of Arthropoda back to com- 

 mon arthropodan ancestors with a definite number 

 of segments and distinctly crustacean in character; 

 then traced these primitive arthropods back to forms 

 like- the nauplius larva of Crustacea, and these in turn 

 to a hypothetical form like the trochosphere larva of 

 recent polychaete annelids. 



Orders of Insects. Linnaeus arranged insects in 

 seven orders, namely, Coleoptera, Hemiptera, Lepi- 

 doptera, Neuroptera, Hymenoptera, Diptera and 

 Apt era. The wingless insects termed Aptera were 

 soon found to belong to diverse orders and the name 

 has become so ambiguous as to meet with little 

 approval. 



From the Linnaean group Hemiptera, the Orthoptera Length, i.28mm. 



After SILVESTRI. 



were set apart the old order Neuroptera a heteroge- 

 neous and unnatural group, was split into several distinct orders, and 

 many other changes in the classification were necessary. 



Without entering any further into the history of the subject, it is 



sufficient to say that increasing discrimination on the part of entomolo- 



has been followed by a gradual increase in the number of order-. 



Naturally, the systems of classification have grown and changed 

 considerably, keeping pace with increasing knowledge. 



Hrauer (1885) made such important contributions to the subject that 

 his system, modified more or less by Packard. Tomstock and others, 

 has been followed for almost forty years. 



