216 



THE COCKROACH 



exception to this small size must be noted in the species from 

 the Jura of Solenhofen, all of which were large and some 

 gigantic, one wing reaching the length of 60 mm., or about the 

 size of our largest tropical Blaberce. If we omit these excep- 

 tional forms, the average length of the wing of the mesozoic 

 Cockroach would be scarcely more than 11 mm. Now an 

 average of the 243 species of which the measurements are 

 given in Brunner's Systeme des Blattaires (1865), gives the 

 length of the front wing of living Cockroaches as a little over 

 18 mm.; so that the mesozoic Cockroaches were as a rule con- 

 siderably smaller, the palaeozoic Cockroaches much larger, than 

 the living. 



Nearly eighty species of mesozoic Neoblattance are known, 

 and they are divided into thirteen genera,* one of which, 

 Mesoblattina (see figure of M. Erodiei), contains upwards of 

 twenty species, mainly from the Lias and Oolites of England. 

 The Upper Oolite has proved the most prolific, considerably 



Fig. 123. MesoNattina Brodiei Scudd. X 4. Purbecks, England. 



more than half the species having been found in the English 

 Purbecks, while nearly a fourth occur in the Lias of England, 

 Switzerland, and Germany. Many of the English species have 

 been figured in Brodie's Fossil Insects of the Secondary Rocks 

 of England, in Westwood's paper on Fossil Insects in the 

 tenth volume of the Quarterly Journal of the Geological 

 Society, and in the memoir alluded to above. No species has 

 yet been found in rocks of different geological horizons, and the 



* See a paper on mesozoic Cockroaches now printing in the Memoirs Bost. Soc. 

 Nat. Hist., Vol. III., p. 439 seq. 



