104 ORTHOPTERA. 



For a description of the structure and life history of 

 this insect, and for theoretical considerations in re- 

 gard to the genealogy and causes of metamorphosis, 

 see The Cocki-oach, Miall and Denny, 1886; also 

 consult Huxley's Invei'tebrata, and RoUeston's Forms 

 of Animal Life. The geological history of the insect 

 is extremely instructive. '' Indeed," says Mr. Scudder, 

 " paleontologically considered, no insect is so inter- 

 esting as the cockroach. Of no other type of insects 

 can it be said that it occurs at every horizon where 

 insects have been found in any numbers ; in no group 

 whatever can the changes wrought by time be so care- 

 fully and completely studied as here ; none other has 

 furnished more important evidence concerning the 

 phylogeny of insects."^ 



The common form of the same group known as the 

 Croton bug {Ectobia germanicd) can be made very 

 useful to students. They can be induced to watch its 

 habits and report upon what they see ; upon its re- 

 markably flattened body and appendages enabling it 

 to crawl into narrow crevices and escape pursuit, its 

 powerful limbs and consequently quick motions, its 

 capacity for ascending even smooth walls, and reckless 

 habit of leaping from any height when alarmed, the 

 strange fact that it uses its wings but rarely and prefers 

 to trust to its legs in trying to escape pursuit. Even 



i Miall and Denny, The Coch'oach, Chap. XI. Also consult 

 Scudder, " Palaeozoic Cockroaches," Mem. Bost. Soc. Nat. Hist., 

 Vol. III., Part I., No. III., 1879; " Mesozoic Cockroaches," Mem. 

 Bost. Soc. Nat. Hist., Vol. III., No. XIII., 1886; and " System- 

 atic Review of our Present Knowledge of Fossil Insects," 

 Bull. U. S. Geol. Surv., No. 31, 1886, 



