318 



THE MICROSCOPE. 



a certain time, divest themselves of their last stin, and appear in the 

 chrysalis form, in which they continue till the succeeding spring, when 

 they assume the perfect beetle ; but remain for a considerable time in 

 a weak state, not venturing out till the fine days of May or the begin- 

 ning of June, at which time the beetle emerges from its retirement, 

 and commits its depredations on the leaves of trees, &c. The antennae 

 have a remarkable comb-shaped appearance, and, with other parts of 

 this insect, generally find a place in the microscopist's cabinet. 



The elytra or wing-cases of the diamond beetles are amongst the 



most brilliant of 

 opaque objects. Some 

 are improved by being 

 mounted in Canada 

 balsam, whilst others 

 are more or less in- 

 jured by it : a trial of 

 a small portion, by 



fig. 148. Meloloniha Vulgaris, or Cockchafer. 



first touching it with turpentine, will decide this point. 



To the genus Ptinus belongs a small- beetle, known as the Death- 

 watch, fig. 149. This and the species Andbium are found in our 

 houses, doing much injury whilst in the larva state. The eggs are 

 often deposited near some crack in a piece of furniture, or on the bind- 

 ing of an old book. As the larvae are hatched, they begin to eat their 

 way into the furniture on which they have been deposited ; and when 

 they have attained a sufficient depth, they undergo their transforma- 

 tions, and return, by another passage, as beetles. In furniture attacked 

 by them, little round holes, about the size of the h«ad of a pin, may be 

 seen j and these are the holes that have been made by the beetles. 

 The noise, which has given rise to the name of death-watch, is made by 

 the insect striking its head against the wood. The larva is called a 

 book-worm when it attacks books ; and old books when seldom used 

 are often found bored through by it. Kirby and 

 Spence mention, that in one case twenty-seven folio 

 volumes were eaten through, in a straight line, by this 

 insect. The beetle is very small, and almost black. 

 The head is particularly small ; and from the promi- 

 nence of the thorax, looks as if it were covered with a 

 fig. Ii9. hood. The Andbium puniceum, fig. 150, attacks dried 

 The Death-watch objects of natural history, and all kinds of bread and 

 (Atropus), biscuits, particularly sailors' biscuits, in which its mag- 

 gots frequently abound. In collections of insects, it 



magnified. 



