173 THE ENTOMOLOGIST. 



by the two distinct dark marks on the thorax; it is a rare 

 insect, but occurs in various parts of London and other towns 

 with foreign trade, but is always very local, inhabiting particular 

 houses. It is a native of Asia and the east of Europe. 



2. Periplaneta, Burm., 1839. 



= Blatta, L. ; Kakerlac, Latr. ; Steleopyga, Fisch. 



Easily distinguished from Panchlora by the long antennae. 



I. (? . Elytra shorter than abdomen. $ . Elytra very small orientalis. 

 II. Elytra as long or longer than the abdomen in both sexes americana. 



1. P. orientalis, L., 1745. =: culinaris, DeGeer. — Not a 

 native of this country, having been introduced from India ; it is 

 the common cockroach, so abundant in our houses ; also occur- 

 ring out-of-doors. 



2. P. americana, L., 1766. — This species is figured in Cuvier's 

 'Eegne Animal,' pi. 77, fig. 4. Larger and handsomer than 

 P. orientalis. Very local, but occasionally found in London and 

 other places, where it has been introduced from abroad ; it is 

 well-established in many houses, and appears to be gradually 

 spreading. 



3. Panchlora, Burm. 

 = Blaberus, L. ? 



1. P. madercB, Fab., is the largest of our Blattidae; it has 

 been occasionally found in London, having been introduced from 

 its native place (Madeira), but is not so well established as 

 P. orientalis and P. americana. 



Achetid^, Leach, 1817. 

 = Gryllid^, Latr. ; Gryllus-Acheta, L. ; Acheta, Fab. 



Four species. Nocturnal, burrowing insects, easily dis- 

 tinguished from the Gryllidae and Acrididas by the horizontal 

 position of the elytra when at rest, and (with the exception of 

 Nemohins) the great length of the wings, which are longer than 

 the elytra ; they stridulate by rubbing the base of one elytron 

 upon the other. Found in woods, gardens, &c. ; one species 

 {A. clomesticus) occurring in houses. 



Table of Genera. 

 I. Elytra much shorter than abdomen. 



1. Very large Gryllotalpa, 



2. Small Nemobius. 



II. Elytra as long as abdomen - - - Acheta. 



1. Gryllotalpa, Latr., 1807. 

 = Gryllus (Acheta), L. 



1. G. vulgaris, Latr., 1807. = Gryllotalpa, L. — Figures of 

 this species will be found in Curtis's ' British Entomology,' x. 

 456; Donovan's 'British Insects,' v. pi. 147; Cuvier's 'Eegne 

 Animal,' pi. 81, fig. 1 ; &c. This remarkable insect cannot be 



