OONSTITUTION AND DEVELOPMENT OF TERMITES. 73 



present possibility of separating the females geuerically. It 

 may be added that, like the antennae, the neuration can vary 

 within limits in the same species, and even on opposite sides 

 of the same individual. Embia urichi, de Sauss., which 

 has been several times referred to, belongs properly to West- 

 wood's subgenus Olyntha. — W. F. H. B.] 



The Embiidae are very remote from the Termitidse, as I 

 have pointed out in the body of my memoir, and they have no 

 more definite affinity with the Perlidse. Even the much-in- 

 voked relationship with the Psocidse is very problematical ; 

 the concentrated nervous system of the latter and their tracheal 

 system (according to researches communicated by Dr. Rovelli) 

 establish a wide difference between the two families. To sum 

 up, the Embiidse approach the Orthoptera (s. str.) more nearly 

 than any other group, though they are separated by a series 

 of important characters. In the present state of our know- 

 ledge I think that they should be ranked among the Orthop- 

 tera (s. lat.), as a special sub-order parallel with that of the 

 Orthoptera (s. str.). 



It seems important to note that my species of Embia has 

 certainly degenerated, a process wiiich has simplified the 

 organism without bringing out any of the characters which I 

 regard as primitive in Thysanura (eleven pairs of stigmata, 

 ocelli with rhabdoms, &c.). Even if we admit that the Thy- 

 sanura have undergone a certain amount of degeneration, and 

 that they once have possessed wings, it must always be recol- 

 lected that they are the degenerate descendants of Orthoptera 

 which retained certain primitive characteristics, which are lost 

 in the Orthoptera of the present day, as far as is known at 

 present. 



My species of Embia is degenerated, or rather, simplified 

 by the loss of its wings. This is probably due to the fact that 

 the species are inhabitants of hot countries, and at the same 

 time of situations neither over-dry nor over-moist. As the 

 lack of a sufficiently warm climate prevents the European 

 Embiidse from acquiring wings before the summer drought 



