1926] 
The Affinities of Gryllohlatta 
81 
of the evolution of the Orthopteran type, the head of a typical 
Blattid or Mantid does not resemble that of a typical Orthop- 
teron as much as the head of a typical termite does, and the 
thoracic sclerites of the Blattids and Mantids are not as similar 
to those of the Orthoptera as the thoracic sclerites of the Isoptera 
are, so that in general, the Isoptera are nearer to the ancestors 
of the Orthopteroids than the Blattids and Mantids are, although 
in the character of their terminal abdominal structures, the 
Blattids and Mantids approach the Orthopteran type more 
closely. 
In the slenderness of the lacinia and galea, the maxilla of 
Gryllohlatta (Fig. 1) resembles that of Gryllotalpa and the Der- 
maptera, but the stipes of Gryllohlatta is not divided into the 
Fig. 1, Ventral (posterior) view of labium, maxilla, and sinistral half of head. 
Fig. 2 Frontal view of head capsule. 
Fig. 3, Ventral (posterior) view of dextral mandible. 
Fig. 4, Antenna. 
peculiar subdivisions present in these two Orthopteroids. The 
maxilla of a typical Isopteron or Blattid would readily serve as 
the starting point for evolving the types of maxillae occurring in 
the Grylloblattids and Dermaptera; and the Isoptera seem to be 
