THE ARTHROPODS 



383 



Thonu? of Butterfly 



Spiracle 



FIG. 



133. Butterfly larva. (From Dickerson's 

 "Moths and Butterflies, 11 Ginn & Co.) 



parts are adapted for sucking nectar of flowers. There are no jaws 

 for biting solid food, but a long coiled tube consisting of two halves 

 closely applied together is the sucking organ. Obviously the butter- 

 fly is, on the whole, 

 built on the grass- 

 hopper plan of struc- 

 ture. 



Larva. Most re- 

 markable about but- 

 terflies and moths is 

 their peculiar devel- 

 opment from egg to 

 larva (caterpillar), 

 then to pupa (which 

 may be in a silky 

 cocoon), and then 

 to perfect insect 

 (imago). 



The larva called 

 " tomato-worm " (which develops into a hawk-moth) is excellent for 

 study. Note: (1) Head, and its parts. (2) Thorax, with three 

 segments, each having a pair of legs. (3) Posterior to these some 

 segments have no legs, and then come some seg- 

 ments with peculiar legs adapted to clinging to 

 twigs (prop legs). (4) A curved spine at pos- 

 terior end. (5) Spiracles or breathing pores 

 along the sides of the body. (6) Color markings 

 in living specimens, if available. 



Pupa. The pupa formed from the tomato- 

 worm is buried in the soil and difficult to find. 

 Pupa from cocoons of Cecropia moth, or other 

 large moths, may be used. The cases or covers 

 of various organs, as shown in Fig. 134, may be 

 seen. Identify the covers of the tongue, an- 

 tennae, legs, eyes, and wings. Note spiracles on 

 sides of the body. Examine the movable seg- 

 ments of the abdomen. 



The fragments to be found in a cocoon at 

 posterior end of a pupa are from the skin which 

 was molted after the cocoon was spun. The larva molts several 

 times before it is full grown and ready to change to pupal stage. 

 Cecropia moths will emerge in February or March from cocoons 



FIG. 134. Pupa of 

 moth, a, antenna 

 case ; w, wing case ; 

 tongue and leg 

 cases between an- 

 tennae ; ab, a b d o - 

 men. (From 

 KinQsley.) 



