102 BRITISH ORTHOPTEKA. 



the most 14 eggs--one seems to have only ten. 

 Nevertheless it may be correct that the normal number 

 is 16. In shape the ootheca closely resembles that of 

 />'. orientalis, but is perhaps a little more rectangular.* 



Rather uniform rich sienna-brown, mottled 



with a lighter tint on the dorsal surface of the thorax. 

 Abdomen darker, legs paler. Cerci straight, lanceo- 

 late, dark. 



VARIATION.- -P. americana is subject to a little 

 variation in size ; otherwise it is fairly constant, 

 except in the mottling of the pronotum. Here the 

 paler tint is sometimes greater in extent and more 

 sharply defined, giving somewhat the appearance of 

 the pronotum of P. australasise. Brunner mentions 

 " varietas pronoti disco toto pallido." 



DATE.- -No doubt the same should be said of this 

 species (and of P. australasiae, and L. surinamensis) 

 as of B. orientalis (p. 97). A P. americana was, 

 however, found at Liverpool Docks, with its ootheca 

 protruding, on 30 December 1904. 



HABITS, ETC.- -P. americana is the largest of the 

 cockroaches that breed in Britain. Apparently there 

 is no likelihood of its being acclimatised out-of-doors, 

 but the list of its adopted haunts under artificial 

 conditions is a long one :- -houses, breweries, bake- 

 houses, warehouses, docks, sugar-refineries, rubber 

 and dye works, nurseries, hothouses, Zoological 

 Gardens, etc. On 23 October 1910 a good number 

 (taken to be this species) were seen in the old 

 insect-house at the Zoological Gardens. They were 

 continually emerging from the grating over the 

 hot-water pipes, and ate readily some sugar put 

 clown for them. Previously, on 22 May 1907, in the 

 insect-house this cockroach was noticed to be quite 

 at home in a free state, and apparently its presence 



* I have oothecse of Ectobius and Elattella, which look' as if they had been 

 deposited in an unfinished state, and so under unnatural conditions. Perhaps 

 this may sometimes help to explain the varying time of carrying the ootheca 

 and the varying interval that elapses before hatching. 



