BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 33 



one pair of abdominal spiracles open into the bubble of trapped air. 

 However, the insect apparently does not use this plastron of air to 

 replenish its tracheal air supply, but, like Rhicnoda natatrix (see 

 below), it inspires air while at the surface through its posterior ab- 

 dominal spiracles and expires air into the bubble under the thorax. 

 While the insect is submerged, the air bubble increases in volume until 

 part of it breaks away and floats to the surface. (Takahashi, 1926.) 



Opisthoplatia orientalis 

 Formosa. — Lives on or in swampy ground (Takahashi, 1924). 



Rhicnoda natatrix 



Sarawak. — Immature cockroaches were found in sodden leaves at 

 the edge of a pool, where they rested for hours at a time. Generally 

 the fore part of the body was in the water but the tip of the abdomen 

 was always in air. When disturbed the insects dived into the water 

 and hid under sticks and stones on the bottom. Air is inspired through 

 the posterior abdominal spiracles, when they projected above the 

 water surface, and expired through the thoracic spiracles. In experi- 

 ments in which the insects' abdomens were held immersed in water, 

 with the thorax exposed, the insects died in 6 to 12 hours or less. (Shel- 

 ford, 1907.) 



Stictolampra buqueti concinula 



Westsumha. — Found under moist fallen leaves on gravelly shore 

 of Melolo River. The nymphs distinguished themselves through their 

 amphibious mode of life and were often good swimmers (Princis, 

 1957a). 



Unidentified epilamprines 



Brazil. — These cockroaches were found under stones at the side 

 of a rocky stream at Ouro Preto. When disturbed they ran down 

 under the surface of the water and hid under stones at the bottom. 

 When thrown on the water surface, they were helpless, and to get 

 beneath the water surface they had to walk down some object. When 

 they had penetrated the surface film they could swim freely. Speci- 

 mens kept in jars lived several days with only a portion of their ab- 

 domens exposed to the air. (Bristowe, 1925.) 



OUTDOOR HABITATS 



This category is a catchall for all cockroaches that are not limited 

 to the more circumscribed habitats that have been previously con- 



