INSECTS 



233 



carriers they are of im- 

 portance. Notice the 

 large compound eyes at 

 the side of the head, as in 

 the grasshopper. The 

 antennae, sensory organs 

 which have to do with 

 hearing and smelhng, are 

 knobbed at the ends. The 

 hairs which cover the 

 body are modified on the 

 wings to form scales. 

 Some of these hairs have 

 to do with the sense of 

 touch. 



The Senses. — Experi- 

 ments may easily be made 

 outdoors in the fall of the 

 year to determine if the 

 butterfly can distinguish 

 color. Make careful note 

 of the different flowers 

 visited by a butterfly dur- 

 ing a given period of time. 

 Are flowers of certain 

 colors visited during that 

 time ? Experiments may 

 also be made to see if the 

 odors of flowers are fac- 

 tors which determine the 

 insects' visits. In most 

 insects the sense of smell 

 is better developed than 

 that of sight. In most 



Monarch butterfly; adults, larva, and pupa on milkweed. 

 From photograph loaned by the American Museum of 

 Natural History. 



butterflies the antennae contain the sense cells which have to do with odor; 

 in some male butterflies, however, a pouch on the wing serves as a help 

 in distinguishing the presence of nectar in a flower. 



Make a drawing of the butterfly, showing as many as possible of the 

 structures mentioned. Carefully label each part. A drawing of the head 



as seen from the side, enlarged about four 



times, will be useful. 



The monarch or milkweed butterfly 

 (Anosia plexippus) is one of our com- 

 monest insects. Its orange-brown, black- 

 veined wings are familiar to every boy or 

 girl who has been outdoors in the coun- 

 tiy during the fall months. The adult 

 female lays her eggs in the late spring 

 on the milkweed. The eggs are fastened 

 singly to the under side of milkweed 



Part of the wing of a moth (Samia), 

 magnified to show the arrange- 

 ment of scales. 



