286 THE INSECT WOBLD. 



among them, the Blatta Germanica and the Blatta Laponica, 

 which are to be met with in the woods round about Paris, have 

 domesticated themselves in dwellings of the northern countries. 

 They are a quarter of an inch in length. The Russians pretend 

 that the former was imported from Prussia by their army, on its 

 return from Germany, after the Seven Years' War (1756 1762). 

 Till this period it was unknown at St. Petersburg, where now-a- 

 days it is met with in great numbers. It lives in houses, and 

 eats pretty nearly everything, but prefers white bread to flour and 

 meat. The Blatta Laponica devours the smoked fish prepared 

 for the winter. 



The Grerman naturalist, Hummel, made some interesting obser- 

 vations on the development and habits of the very prolific Blatta 

 Germanica. It lays its eggs in a silky capsule, which is in the 

 form of a bean, with two valves in the interior. This is drawn 

 about for some time appended to the extremity of the abdomen, 

 and after a time abandoned. 



Hummel placed under a bell-glass a female cockroach and a 

 perfect egg-pouch, which had only just been abandoned by 

 another female. He saw the cockroach approach the bag, feel it, 

 and turn it about in all directions. She then took it between her 

 front legs, and made a longitudinal opening in it. As the opening 

 grew wider, little white larvae were seen to come from it rolled up 

 and attached two together. The female presided at this operation. 

 She assisted the larvse to set themselves free, drawing them out 

 gently with her antennae. In a few seconds they were able to 

 walk, when she ceased to trouble herself about them. 



The larvse change their skin six times before reaching the per- 

 fect state. "When they come out of their skin they are colourless, 

 but the colour comes in a few minutes. At the fifth moult, which 

 takes place three months after birth, they become pupae, with 

 rudimentary wings, the whole shape of the insect being well 

 marked. The sixth, or last moult, takes place at the end of six 

 weeks. The pupa is now changed into a perfect insect. The 

 female is distinguished from the male by the greater size of her 

 abdomen. 



The most destructive of the Blattce, or Cockroaches, are those 

 which have been imported into Europe by the ships coming from 



