632 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



the " superordo Orthoptera s. lat.," and divides it into two suborders; 

 the simpler, or that of the Entotrophi, contains the two families 

 Campodeadse and Japygidae, and the Ectotrophi, the MachilidsB and 

 Lepismidse. In the former the buccal apparatus is partly retained within 

 the head and partly fused into a lower lip ; in the latter there are 

 external gnathites and the lower lip is deeply divided. 



The Entotrophi may have eleven, tbe Ectotrophi never have more 

 than ten stigmata ; in the former the Malpighian tubes are rudimentary, 

 while they are well developed in the latter. These and other characters 

 which are duly enunciated justify the division into these two suborders. 



The next question discussed is what relations have the Thysanura 

 with the different orders of insects proposed by Brauer and with the 

 CoUembola. The author regards the Thysanura as the lowest order of 

 Orthoptera (^sens. lat.), and the other Orthoptera as being derived from 

 Insects allied to them. 



Thysanura 

 Thysanura 



Endotropha 

 Ectotropha 



b 



B 



o 



o 



o 





O 

 o 



hj 



The superorder of Orthoptera might be called the Protentoma and 

 all other Insects the Metentoma. The author regards as the most 

 important result of his researches the full justification of the hypothesis 

 that the Thysanura are the most primitive Insects that we know, at 

 least in the greater number of their organs. Further researches on the 

 CoUembola will probably lead to their being placed with the entotrophic 

 Thysanura. Prof. Grassi's views as to the relationship which obtains 

 between the various groups of the Arthropoda are shown in the following 

 table : — 



Arachnida arthrogastra (Araneida) 

 Pqecilopoda 



Phyllopoda (Crustacea) 



Symphyla (Myriopoda) 



Thysanura (Protentoma or 

 Insects in general) 



Peripatus 

 Chilopoda 



