BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 325 



by different workers, which only further observation and experimenta- 

 tion will explain. Some of the reported observations are unique; this 

 is especially true for the feral species. Because of the paucity of in- 

 formation, it is impossible at this time to make valid generalizations 

 about some of these interesting relationships. 



FAMILIAL ASSOCIATIONS 



The females of many species of cockroaches insure varying degrees 

 of protection to the developing young in their ways of disposing of the 

 ootheca after it has been formed. The extent of this association be- 

 tween the mother and her developing progeny varies from the mini- 

 mum amount of time spent by oviparous females in concealing their 

 oothecae, to the duration of embryogenesis in the so-called viviparous 

 species, a period of over a month or more. 



Haber (1920a) observed a female of Periplaneta americana chew a 

 groove in a piece of pasteboard into which she attempted to deposit 

 her ootheca. The ootheca failed to adhere to the shallow hole and fell 

 to the floor. After several futile attempts to replace the ootheca in the 

 hole, the female finally left the tgg case on the floor of the cage and 

 coated it with an oral secretion to which she attached bits of trash. 

 During this operation she chased other females away when they 

 ventured near the site. Qadri (1938) described the behavior of the 

 female of Blatta orientalis in concealing her ootheca in a hole that she 

 dug in sand ; she deposited the egg case in the hole, coated it with 

 saliva and sand, and then refilled the pit. Rau (1943) described in 

 detail how females of P. americana and B. orientalis covered their 

 oothecae with wood dust or sand in holes they had prepared in the 

 substrate. Both species placed a sticky oral secretion in the holes and 

 then deposited their oothecae therein. After coating the oothecae with 

 more sticky secretion, the females adjusted the oothecae so that the 

 keels were uppermost and then carefully concealed the oothecae with 

 the excavated debris. Both females spent over an hour in the act. 

 Rau (1924) previously reported that of 90 oothecae deposited by B. 

 orientalis in jars containing earth and trash, 36 were placed in crev- 

 ices or excavated holes, and 38 were hidden by being covered with dirt 

 stuck to them with saliva; only 16 were left uncovered. 



Edmunds (1957) described oviposition by Periplaneta brunnea. 

 Some females spent from 30 to 40 minutes secreting from the mouth 

 a frothy substance that was smeared on the substrate ; the egg cap- 

 sule was deposited in the secretion and covered with additional froth, 

 which hardened into a very strong cement. Some females spent as 



