CHARACTERISTICS OF INSECTS 75 



Some species of ants are among the most warlike of any insects. In 

 the case of the robber ants, which live entirely by war and pillage, the 

 workers have become modified in structure, and can no longer work, 

 but only fight. Some species go further and make slaves of the ants 

 preyed upon. These slaves do all the work for their captors, even 

 to making additions to the nest and acting as nurses to their young. 



Practical Exercise 5. Report on the life in an ant colony in South America as 

 described in Beebe's Jungle Days, or the life of the army ants, Chapter xiv, in 

 Howe's Insect Behavior. 



Self-Testing Exercise 



Some wasps lead (1) lives but most (2), (3), 



and wasps show (4) life. In the case of the honeybees we 



have a (5) with a single fully-developed (6) or 



(7), several hundred (8) or (9) and man? 



thousands of (10). The latter have many duties such as 



gathering (11) and (12) from flowers, (13) 



the young, (14) and (15) the hive. They also make 



(16), which they store in cells made of (17). Ants 



also have a complicated communal life, some acting as (18), 



others as (19), and still others as (20). The com- 

 munal life of ants is dependent upon (21). Each colony seems 



to have its own peculiar (22). Bees, ants, and wasps belong to 



the order (23). 



PROBLEM V. WHAT ARE THE CHARACTERISTICS OF OTHER 

 GROUPS OF INSECTS? 



The Flies. There is an order of insects called Diptera, which 

 is characterized by having only two gauzy wings. The members of 

 this group of insects frequently found on a field trip are mosquitoes, 

 gnats, botflies, and the house fly. 



The head of the common fly is freely movable and is provided 

 with mouth parts for sucking and lapping. The foot shows wonder- 

 ful adaptation for clinging to smooth surfaces, as it is provided with 

 sticky pads bearing tubelike hairs. 



The second pair of wings is changed into a pair of small knobs, 

 called balancers. This name suggests their use, for if they are re- 

 moved, the fly is unable to balance itself. 



The development of the fly is extremely rapid. A female may 



