230 ORTHOPTERA 



the skin an uncertain number of times — not less than five, 

 probably as many as seven — it reaches the adult condition, the 

 changes of outer form that it undergoes being of a gradual nature, 

 except that at the last ecdysis the wings — in the case of the 

 winged species — make their appearance, and the terminal 

 segments of the body undergo a greater change of form. What 

 mutations of shape may be undergone by the thoracic segments 

 previous to the final production of the wings has not apparently 

 been accurately recorded, Fischer's opinion being evidently based 

 on very slight observation. The little that has been recorded as 

 to the post-embryonic development since the observations of 

 Hummel ^ and Cornelius ^ will be found in the works of Brunner.^ 

 According to this latter authority, in the wingless species the 

 terminal segments of the body have the same form in the early 

 stages as they have in the adult state, so that this latter condition 

 can only be recognised by the greater hardness of the integument. 

 When tegmina or wings are present in a well-developed form in 

 a Blattid, it is certain that the Insect is adult ; and when there 

 can be seen at the side of the mesonotum or metanotum a piece, 

 however small, separated by a distinct suture, it may be correctly 

 assumed that the individual is an adult of a species having only 

 rudimentary alar organs. The adult female of the common 

 Stilopyga orientalis shows this phenomenon. 



The cockroaches are remarkable for the excessive rapidity 

 with which they run, or rather scurry, their gait being very 

 peculiar. The common domestic forms, when alarmed, disappear 

 with great agility, seeking obscure corners in which to hide 

 themselves, it being part of their instinct to flee from light. 

 Hence they are called lucifugous, and are most of them entirely 

 nocturnal in their activities. In the South of Europe and other 

 warmer regions many Blattidae may, however, be found on bushes 

 and foliage in the daytime ; these, when alarmed, fall down and 

 run off with such speed and in so tortuous a manner, that it 

 is a very difficult matter to seize them. It is recorded that the 

 males of the genus Heterogamia are attracted by lights, though 

 their apterous females keep themselves concealed underground in 

 sandy places. 



^ Essais entomologiques, St. Petersburg, 1821. 



" Beitracje zur niiheren Kenntniss von Periplaneta orientalis, Elberfeld, 1853. 



^ Nouv. Syst. BlcMaires, 1865, p. 16, etc. 



