CHAPTER II 



The Parts of an Insect's Body 



The Head 



Adult insects have a more or less distinct head, varying greatly in 

 shape according to the habits of the species. 



Prominent on either side, near the top of the head, are usually to be 

 seen the compound eyes. These 

 are very large in some groups, 

 such as the horseflies or dragon 

 flies, which need to have espe- 

 cially good vision, but are absent 

 in some other groups, such as 

 certain parasites, which have little 

 need of the ability to see. A com- 

 pound eye is made up of many 

 lenses, each with its own sensi- 

 tive area and nerve. The num- 

 ber of these lenses often is great ; 

 the common house fly has about 

 4000 on each side. 



Between or above the compound 

 eyes are usually three simple eyes. 

 out readily by looking closely. 



Near the compound eyes are the antennae, or " feelers." Their 

 shape is diverse with the different groups, and is one of the valuable 

 means of determining the identity of many insects, or of placing a 

 specimen in its proper group. Eight or ten general types of antennae 

 are recognized. 



7 



Fig. 4. — Head of a beetle, showing 

 mouth parts. Enlarged and natural 

 size. Original. 



These are small, but can b^ made 



