1919] Walker: Structure of Orthopteroid Insects 303 



which have otherwise disappeared, together with the inner 

 valvulas. The remainder of the ventral surface of segments 

 nine and ten is covered with a thinly chitinized cuticle. 



In Fig. 63 the eighth abdominal spiracle may be seen in 

 the conjunction immediately behind the eighth sternum, and 

 close to the lateral margin, a position similar to that which it 

 occupies in Parcoblatta. 



It is sufficiently evident that the terminal abdominal struc- 

 tures of Termopsis are essentially like those of a Blattid in which 

 the ovipositor has nearly disappeared. * In Leucotermes it 

 has quite vanished and the cerci are reduced to two segments. 



Judging by the more uniform length of the abdominal 

 tergites, the cylindrical form of the cerci, and many other 

 characters in other regions of the body it is probable that the 

 ancestors of the Isoptera were more primitive than any Blat- 

 toidea of recent age, but the genitalia are distinctly more 

 suggestive of the Blattids than the Mantids, and the wing 

 venation of the primitive New Zealand termite Mastotermes, is 

 decidedly more like that of the Blattoidea than the Mantoidea 

 or.Protoblattoidea, so that I am inclined to consider the order 

 Isoptera as an offshoot from primitive Blattoid stock. 



The results of these studies" of the genitalia of the Mantoidea, 

 Blattoidea and Isoptera strongly support Crampton's grouping 

 of these orders in a superorder " Panisoptera. " 



Dermaptera. 



In this order the genital segments are so highly modified 

 that they give little information that is of value in determining 

 the systematic position of the order. While in the majority 

 of forms the ovipositor is entirely lacking, a small one is present 

 in some genera of Protodermaptera, notably in the families 

 Pygidicraniid® and Echinosomidas (Zacher, '11),^^ so that we 

 may conclude that the absence of this structure is a secondary 

 condition. I have not seen any of these ovipositor-bearing 

 forms, having, in fact, examined critically only two species 

 of the order, viz., Forficula auricularia L. and Anisolabis 

 maritima Bon. I have reproduced, however, figures of the 

 ovipositor of i^a/ocrawm and Echinosoma from Zacher {loc. cit.). 



21 Zacher, Friedrich, Zool.Jahrb., Bd. XXX, Syst., pp. 303-400, 80 Figs. (1911). 



