36 
Psyche 
[February 
ON THE AFFINITIES OF THE GRYLLOBLATTIDiE 
By A. D. Imms, D. Sc., 
Rothamsted Experimental Station, Harpenden, England. 
The family Grylloblattidse includes two known genera viz* 
Gryllohlaita Walk. (N. America) and Galloisiana Caudell (Japan). 
In its morphological characters it is evidently the most primitive 
living family of Orthopterous insects. Viewed from the phylo- 
genetic standpoint, the Grylloblattidse are of exceptional interest 
in that they combine features of the Orthoptera ( sensu lat.) 
Isoptera, Dermaptera and Embioptera. Most of these characters 
have already been pointed out by Walker (1914) and in a series 
of papers by Crampton. The possession of a combination of 
“synthetic” characters, that are exhibited also in other groups, 
has rendered it difficult to settle the taxonomic position of the 
Grylloblattidse and the affinities of the latter have consequently 
given rise to some divergence of opinion. In so far as the main 
characters are concerned, Walker considered that they are nearest 
allied to the family Blattidse of the Orthoptera Cursoria. The 
present writer (1925) also maintained that the Grylloblattidse 
are more closely related to the Cursoria than to the Saltatoria. On 
the other hand, Crampton in his most recent publication (1926) 
on the subject emphasises his previous opinion that the family 
should be placed along with the Orthoptera Saltatoria. In en- 
deavouring to clear up the cause of this bone of contention it is 
useful to enumerate the principal characters that distingiuish 
these two main divisions of the old order Orthoptera and they 
are summarised below. 
ORTHOPTERA CURSORIA. (Blattidae and Mantidse, to- 
gether with the more distantly related Phasmidse). Legs usually 
of approximately equal size and the hind pair not modified for 
leaping: tarsi 5-jointed. Sound producing organs wanting. 
Cerci most often multiarticulate, often with 8 to 15 or more 
joints. Ovipositor reduced and concealed. Penis asymmetrical. 
ORTHOPTERA SALTATORIA (Orthoptera sensu stricto : 
Acridiidse, Tettigoniidse and Gryllidse). Legs of unequal size, 
