DEVELOPEMENT OF SEGMENTS. 181 



The thirteen segments which compose the body of the 

 larva bear the following relation to the distribution of the 

 segments in the imago. The first segment or head of the 

 larva becomes the head of the imago ; the three following 

 segments compose the thorax, and the remainder become the 

 abdomen in the perfect insect. Dr. Ratzeburg has, indeed, 

 lately published a memoir, endeavouring to prove that the 

 two first segments of the larva of the aculeate Hymeno- 

 ptera become the head of the imago ; but the observations of 

 this author, as I have proved more than once, are incorrect, 

 and founded upon very unphilosophical views. 



In the Monomorphous division the larvae greatly resemble 

 the perfect insect, differing chiefly in being entirely destitute 

 of any appearance of the organs of flight. The third seg- 

 ment of the body also does not exhibit the shield-like scu- 

 tellum which is found in the imago in that situation : here 

 belong the various tribes of locusts, grasshoppers, and 

 crickets (fig. 11, larva of the cricket), bugs (fig. 12, larva of 

 a Pentatoma), tree and frog-hoppers, cockroaches, praying 

 mantes, &c., constituting the orders Orthoptera, Hemiptera, 

 and Homoptera, as well as some portions of the order Neu- 



roptera. Some of these insects are, however, remarkable 

 for being destitute of wings in the perfect state, and a diffi- 

 culty thence arises of distinguishing the larva from the sub- 

 sequent states. The variation in their size, and the constant 



