ITS ZOOLOGICAL POSITION. 



15 



. Family Blattina. Body usually depressed, oval. Pronotum 

 shield-like. Legs adapted for running only. Wing- 

 covers usually leathery, opaque, overlapping (if well 

 developed) when at rest, anal area defined by a furrow 

 (fig. 4). Head declivent, or sloped backwards, retractile 

 beneath the pronotum. Eyes large, ocelli rudimentary, 



usually two. antennae long and slender. 



*/ ^-j 



intcrno-median area 



I'F.IKS 



Fig- 4. Generalised sketch of Cockroach wing-cover. 



About eight hundred species of Cockroaches have been 

 defined, and to facilitate their arrangement, three groups have 

 been proposed, under which the different genera are ranked.* 



Group 1. Both sexes wingless (Polyzosteria). 



Group 2. Males winged, females wingless (Perisphceria, 



Heteroyamia). 



Group 3. Both sexes with more or less developed wings 

 (about 7 genera). 



* For descriptions of the species Fischer's Orthoptera Europsea (1853) or Brunner 

 von*>Wattenwyl's Nouveau Systetne des Blattaires (1865) may be consulted. The 

 classification adopted by the last-named author is here summarised. 



BLATTARI.E. 

 A. Femora spinous (Spinosce). 



Fam. 1. Ectobidce. Seventh abdominal sternum undivided in female. Sub- 

 anal styles absent in male. Wings with triangular apical area. Ectobia, 

 including E. lapponica (Blatta) and other genera. 



Fam. 2. Phyttodromidce. Seventh abdominal sternum undivided in female. 

 Sub-anal styles usual in male (0 or rudimentary in Phyllodromia). Wings 

 without triangular apical area. Phyllodromia, including P. germanica (Blatta) 

 and other genera. 



Fam. 3. Epilampridce. 



Fam. 4. Periplanetidce. Seventh abdominal sternum divided in female. 

 Sub-anal styles conspicuous in male. Polyzosteria t Periplaneta, &c. 



B. Femora not spinous (Muticce)- 



Families. Chorisoneuridce, Pancliloridce, Perisphceridce, Corydldce, Hetero- 



gamidce, Blaberidce, Panesthidce. 



Many useful references will be found in Scudder's Catalogue of N. American 

 Orthoptera, Smiths. Misc. Coll., viii. (1868). 



