BLATTODEA. < J 



but a dwindling remnant of a dying race. Let the 

 careful housewife find in this fact what consolation 

 she can : at any rate she may rejoice that the Carbo- 

 niferous period is past and that she is not required to 

 combat the host of cockroaches which luxuriated in 

 the warm, moist climate of that far-distant age. 



If we were to admit to the British list all the 

 cockroaches which under any circumstances have 

 occurred in Britain, the number of species would be 

 quite considerable. It would be necessary to group 

 them in three categories : 



a. Three natives, that is, undoubtedly indigenous species. 



b. Five naturalised aliens,* which seem now to be thoroughly 

 established and to breed here, though not under natural 

 conditions. 



c. Casual visitors a large number, which should not, 

 however, appear on our list, and which therefore I shall do 

 little more than mention. 



In the first group are three insects only : Ectobl/'x 

 ll>ponicm Linn., E. perspicillaris Fuessly, and E. 

 panzer i Steph. All live out of doors, on bushes, 

 amongst herbage, and in similar situations. They are 

 small, active insects, very delicate in structure, and 

 with nothing at all repulsive in their appearance 

 (PL VIII). Of the five in the second group Blattn 

 orientalis Linn, has been long established; Blattella 

 germatiira Linn, and Periplaneta americana Linn, were 

 the next to settle down amongst us; P. australasise 



o * 



Fabr. followed later; while Leucophssa surinamensis 

 Linn, is quite a recent introduction to our fauna. 

 Of the casual visitors none seem at present to show 

 any inclination to establish colonies in the British 

 Isles. 



' Shelford (' Ent. Rec.' 1912, p. 217) considered the following five species 

 to be cosmopolitan : (I) Blattella germanica Linn. (2) Periplaneta ameri- 

 cana Linn. (3) P. australasiae Fabr. (4) RhyparoMa maderse, Fabr. (5) 

 Leucophaea surinamensis Linn. Blatta orientalis Linn, is also of wide distri- 

 bution. All except B. orientalis are properly tropical insects, though they 

 may sometimes extend into temperate regions, where, however, they do not 

 seem able to establish themselves naturally. 



