358 



MESOZOTC INSECTS OF QUEENSLAND. 



No.G. Blattoidea. 



By R. J. Tillyard, M.A., D.Sc, F.L.S., E.E.S., Linnean 

 Macleay Fellow of the Society in Zoology. 



(Text-figs. 29-40). 



Although regarded by many entomologists as forming only a 

 single family, or at most a Suborder, within the Order Ortho- 

 ptera, the Cockroaches comprise the vast majority of the known 

 fossil insects of Paheozoic times, and were evidently the dominant 

 group during the Upper Carboniferous and Permian of the 

 Northern Hemisphere. Consequently, they have come to be 

 studied apart from the rest of the Orthoptera; and many attempts 

 have been made to indicate for them characters of ordinal value, 

 which should set them completely apart from the rest of that 

 Order. Such characters are to be found in the oval, much 

 flattened body; the large oval pronotum, beneath which the head 

 is almost wholly concealed; the huge coxae; the similarity in the 

 structure of all three pairs of legs; and especially in the shape 

 and venation of the tegmina or forewings. I must confess my 

 inability, at present, to see anything of more than subordinal 

 value in all these characters. The Cockroaches appear to me to 

 be essentially the most generalised of Orthoptera; and I propose 

 to use the group-term lilattoidea as indicating a distinct, archaic 

 Suborder within the Order Orthoptera. 



The great majority of fossil cockroaches are represented either 

 by a single tegmen, or part of it, or at most by the two tegmina 

 in situ, folded down the back of the insect. Hind wings are 

 comparatively rare, awing to their much greater delicacy of 

 texture, and the slight chance of their being preserved intact, 

 or, if preserved, of leaving any reasonably clear impression upon 

 the rock in which they become imbedded. 





