Objects for the Microscope. 75 



capable of elevation and depression. The whole grinding 

 machine is moved by thousands of muscles, which enable it 

 to reduce the food to a pulp, and it is then passed on to the 

 intestinal canal or lower stomach, where biliary vessels, 

 analogous to the liver in the higher animals, pour in the 

 bile, which finally prepares the food for the general nourish- 

 ment of the body. 



A most interesting collection of gizzards may easily 

 be made, and the variation and adaptation of structure 

 observed, by preparing the stomach of Dytiscus, of the 

 large Grasshopper or Locust, the Cockroach (Blaps), Tene- 

 brio (Beetle) and most of the predaceous Beetles. One 

 small Beetle, a wood-borer, Cryptorhynchus lapathi, has a 

 gizzard so minute as hardly to exceed a large pin's head in 

 size, and yet it is said to be armed with no less than 400 

 pairs of teeth, moved by a far greater number of muscles. 



MOUTH OF BEETLE. 

 (Telephora, or Soldier-beetle.) 



This is a common and favourite object, and should be 

 considered carefully, for it belongs to that large and useful 

 tribe of insects which we could no more spare from their 

 place in creation than we could the flowers of the field, or 

 the birds of the air. 



A Beetle's mouth will be more interesting if we say a few 

 words about the Beetles themselves. 



Coleoptera they are called, from two Greek words, signi- 

 fying " wings in a sheath." No less than 30,000 species 

 are known, of which 3,600 are found in Britain ; exceeding 

 the amount of all our other native animals, and forming 

 a third part of our insect population. They vary in size 

 from the great Prionus, which measures six inches long, and 

 has nine inches expanse of wing, to the minute Trichopteryx 

 and Atomaria, hardly one-eighth of a line quite micro- 

 scopic ; and yet every external joint, every internal organ, 

 is as perfect in the small as in the large. 



The usefulness of the Beetle tribe is far greater than is 

 imagined. Not only in the perfect state do they remove 

 dead animal substances, excrements, &c.,but in their larval 



