124 Psyche [October 



Hymenoptera occupy a position somewhat intermediate between 

 the Psocida and Neuroptera, but they are also very closely related 

 to the Coleoptera, and it is very probable that their ancestors were 

 anatomically intermediate between the Zoraptera (with the Isop- 

 tera) and the Coleoptera (with the Dermaptera), The Mecop- 

 tera (and Trichoptera) are quite closely allied to the Hymenoptera 

 on the one hand, and the Neuroptera on the other, although their 

 closest affinities are with the Neuroptera, such Neuroptera as 

 Nemoptera being extremely like the forms giving rise to the Mecop- 

 tera and to the Diptera, w^iich were derived from Mecoptera-like 

 forebears. The Trichoptera and Lepidoptera, although related to 

 the Mecoptera also, were probably derived from Neuropteroid 

 ancestors closely resembling the Ithoniidse (such as Oliarces) . The 

 Neuroptera themselves are extremely closely related to the Coleop- 

 tera, and doubtless arose from ancestors intermediate between the 

 Coleoptera (with the Dermaptera and Embiidina) and the Zorap- 

 teron-Isopteron group — in other words, the lines of, descent of the 

 Psocida?, Hymenoptera, Neuroptera and other insects at the base 

 of the stem of the higher forms converge to a point intermediate 

 between the Zorapteron-Isopteron group on the one side, and the 

 Coleopteron-Dermapteron group (with the Embiidina) on the 

 other; so that these groups are of the greatest phylogenetic inter- 

 est, not only from this fact, but also from their position on either 

 side of the stem forms from which the Orthopteroid insects were 

 likewise developed. 



With regard to the grouping of the different insect orders into 

 superorderSjHhereare apparently eight principal superorders in the 

 class Insecta. Of these, the superorders Panprotura and Panthys- 

 anura belong in the subclass Apterygota, while the other six belong 

 in the subclass Pterygota. The principal representatives of these 

 superorders are as follows: 

 Proturoid Superorder (Panprotura) 



Protura, Entomobryoida, Sminthuroida, etc. 

 Thysanuroid Superorder (Panthysanura) 



Canipodeoida,^ Lepismatoida, Machiloida, etc. 



' If it be advisable to restrict the termination "piera" to groups of ordinal rank, the above- 

 mentioned eight superorders might be termed the Poduriformia, Lepismiformia, Ephemeri- 

 formia, Perliformia, Phasmiformia, Blattiformia, Psociformia, and Siahformia. 



' A study of the anatomical details of Campodea, Projapyx, Japyx, etc., has shown that these 

 insects belong to a single order, and that the division into Rhabdura and Dicellura is of subordi- 

 nal value only. 



