THE COMMON COCKROACH 125 



time sexually mature, and possess for the first time the 

 power of procreation. 



There are many other insects which develop in a 

 similar way, as, e.g., earwigs, field-bugs and the bed- 

 bug, frog-hoppers and tree-hoppers, lantern- flies, dragon - 

 flies, grasshoppers, locusts, and crickets. All these, 

 together with the cockroaches, as they are active 

 throughout the whole of their life, and pass into their 

 final forms by gradual and slight changes instead of by 

 sudden and strongly marked ones, are said to undergo 

 an "incomplete metamorphosis," and are, for that 

 reason, described as " hemimetabolic." But, on the other 

 hand, the true beetles, together with bees, ants, and 

 wasps, butterflies, moths, flies, and fleas never develop 

 in this way, but always lose their powers of locomotion 

 and eating, and become dormant and inactive as a 

 chrysalis for a certain time immediately before assuming 

 their final shape, and appear in at least three totally 

 distinct forms in the course of their life : such are said 

 to undergo a " complete metamorphosis," and are there- 

 fore described as " holometabolic." From this it is 

 evident that the cockroach, the changes in which are 

 so slight as scarcely to deserve the name of meta- 

 morphosis at all, is not a beetle in fact, its nearest 

 allies are the crickets, locusts, and grasshoppers, with 

 which and a number of less familiar insects, such as the 

 curious exotic walking-sticks and walking-leaves, it con- 

 stitutes the order Orthoptera, a group entirely distinct 

 from the Ooleoptera, or true beetles. Of this order, the 

 cockroaches form a numerous and important section, 

 usually called Blattina or Blattidce, of which upwards of 

 800 existing species have already been described. 



Some very curious phenomena occur in connection with 

 the formation and deposition of the eggs. These are 



