934 NATURAL HISTORY. 
: Fig. 184.—Magnified Eggs of various Insects. 
that is, 1,000,000,000,000,000,000. But they are so feebly 
constructed that a large portion of them are destroyed 
in one way and another before they come to maturity. 
Insects are distributed largely over all parts of the globe, 
appearing even in the arctic regions during their short 
summers. They are the most abundant in the tropical 
regions, and there the largest and most brilliant species 
are found. Each region has Insects peculiar to itself. 
Some, however, are very widely distributed, the com- 
mon House Fly the most widely of all. 
Questions.—What is the meaning of the term Invertebrate ? What 
are included in the sub-kingdom of the Articulata? In what are they 
alike? What is said of the arrangement of the skeleton-covering of 
the Articulata? What is said of their nervous system? What of 
their muscles? What of their jaws? What of their circulation? 
What of their respiratory organs? How do they differ from the Ver- 
tebrates in symmetry? Give the classes of the Articulata, with their 
characteristics. What is said of the number of Insects? Show the 
appropriateness of the name Insect. escribe the respiratory appa- 
ratus of Insects. What do Insects live on? Describe the mandibu- 
late apparatus. Describe the haustellate apparatus. What are some 
of its variations? What is said of the antenne ? What of the palpi? 
What is said of the senses of Insects? Describe the arrangement of 
the eyes of a Bee. What is said of the digestive organs of Insects? 
