34 



of both wings and elytra of fossil forms. Since Palaeozoic times 

 cockroaches appear to have decreased in numbers greatly, if not so 

 much in size, and they must now be looked upon as but a dwindling 

 remnant of a dying race. Let the careful houseAvife find in this 

 fact what consolation she may, and at any rate rejoice that she does 

 not live in the Carboniferous period and have to combat the hosts 

 of cockroaches that luxuriated in the warm moist climate of that 

 far distant age. 



Artifical Key to British Blattodea. 



A. Indigenous ; living under natural conditions ; 



small. 



(a) Pronotum dark, with pale margins . . 

 (&) Pronotum pale, with dark markings on 



disc ; very small 

 (c) Pronotum pale, with a few dark dots . . 



B. Naturalised; living under artificial conditions ; 



larger. 



(a) Dark ; wings rudimentary in female, 



truncated in male 

 (6) Wings developed in both sexes. 



1. Grey-brown ; two dark lines on 



pronotum ; rather small species 



2. Sienna-brown ; pronotum nearly 



concolorous ; large species 



3. Sienna-brown ; pronotum with 



yellow margin ; mediastinal area 

 yellow ; large species . . 



4. Very dark; pronotum chiefly 



black ; size moderate . . 



If we were to admit to the British list all the cockroaches which 

 under any circumstances have occurred here, 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 fair 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 : — Ectobius lapponicus, 

 Linn. ; E. pameri, Steph., and E. i>erspicillaris, Fuessly. 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. 



Ectobius lapponicus, Linn., though the largest of native 

 British cockroaches, measures but 20mm. in wing-expanse in the 

 male, the female is smaller still. Its darker colour separates it from 

 E. perspicillaris, which is of nearly the same size, while its larger 



* Approximate length from front of head in resting position to tip of 

 abdomen. 



