358 MR. ROBERT S11ELFORD OX 



[From the Proceedings or the Zoological Societi <>r London, 



1912.] 

 [Published June 1912.] 



Mimicry amongst the Blattidse ; with a Revision of the 

 Genus Prosoplecta Sauss., and the Description of a new- 

 Genus. By Robert Shklford, M.A., F.Z.S. 



(Plate XLVIII.* and Text-figures 42-46.) 



Speaking in general terms the Blattidse may be regarded as a 

 somewhat defenceless group of insects, preyed upon by numerous 

 enemies both vertebrate and invertebrate, to escape which they 

 must rely on their skulking, cryptic habits, and on a high degree 

 of speed when disturbed. In accordance with their cryptic mode 

 of life most cockroaches are obscurely coloured, harmonising 

 more or less perfectly with their inanimate surroundings, or, at 

 any rate, displaying no conspicuous markings to attract the 

 attention of potential foes. 



Exceptions to this cryptically coloured type of cockroach, how- 

 ever, exist in some numbers and are dealt with in the following 

 pages. 



The Australian continent is the headquarters of a group of 

 Blattidse which presents all the features customarily associated 

 with extreme unpalatability. This gronp is the Polyzosteria 

 section of the sub-family Blattinse. Nearly all the species are 

 apterous and expose themselves freely, and many air endowed wit !i 

 a most repulsive odour. Mr. W. W. Froggatt informs me that 

 Polyzosteria limbata Burm., /'. cuprea Sauss., and others of this 



* For explanation of the Plate see p. 376. 



[2] 



