ix FOSSIL COCKROACHES 239 



have already said, that in the Palaeozoic epoch Insects similar to 

 our existing cockroaches were abundant, their remains being- 

 found in plenty in the coal-measures both of Europe and North 

 America. Fig. 133, B, shows a fossil tegmen of Etdblattina 

 manebachensis from the upper Carboniferous beds of Ilmenau 

 in Germany. It will be noticed that the disposition of the 

 nervures is very much like that which may be seen in some 

 of our existing Blattidae (cf. the tegmen of Blabera, Fig. 

 132, A), the vena dividens (a) being similarly placed, as is 

 also the mediastinal vein on the front part of the organ. 

 The numerous carboniferous Blattidae have been separated as a 

 distinct Order of Insects by Scudder under the name Palaeo- 

 blattariae, but apparently rather on theoretical grounds than 

 because of any ascertained important structural distinctions. He 

 also divided the Palaeoblattariae into two groups, Mylacridae and 

 Blattinariae, the former of which was supposed to .be peculiar 

 to America. Brongniart has, however, recently discovered that 

 in the Carboniferous deposits of Commentry in France Mylacridae 

 are as common as in America. This latter authority also states 

 that some of the females of these fossil Blattidae are distinguished 

 by the presence of an elongate exserted organ at the end of the 

 body. He considers this to have been an ovi- 

 positor by which the eggs were deposited in 

 trees or other receptacles, after a manner that 

 is common in certain Orthoptera at the present 

 day. If this view be correct these Carbon- 

 iferous Insects must have been very different 

 from the Blattidae of our own epoch, one of 

 whose marked characteristics is the deposition 

 of the eggs in a capsule formed in the body of 

 the parent. 



In the strata of the secondary epoch re- 

 mains of Blattidae have also been discovered 

 in both Europe. and America, in Oolitic, Liassic, 

 and Triassic deposits. From the Tertiary 

 strata, on the other hand, comparatively few FlG i34._Front leg 

 species have been brought to light. A few of Peripianeta 



-, i T , . , australasiae. 



have been discovered preserved in amber. 



The classification of the Blattidae is attended with considerable 

 difficulty on account of the numerous wingless forms, and of the 



