Illustrated Studies 



93 



Illustrated Study of Insect Pests (Figs. 171-176). Why does the clothes 

 moth (171) lay its eggs upon woolen clothing ? How does the larva conceal itself? 

 The larva can cut through paper and cotton, yet sealing clothes in bags of paper 

 or cotton protects them. Explain. 



The house fly eats liquid sweets. It lays its eggs in horse dung. Describe its 

 larval and pupal forms. Banishing horses from city would have what beneficial 

 effect ? 



Describe the louse and its eggs, which are shown attached to a hair, natural size 

 and enlarged. 



Describe the bed bug. Benzine poured in cracks kills bed bugs. Do bed 

 bugs bite or suck ? Why are they wingless ? 



Describe the larva, f, pupa, g, and the adult flea, all shown enlarged. Its 

 mandibles, b, b, are used for piercing. To kill fleas lather dog or cat completely 

 and let lather remain on five minutes before washing. Eggs are laid and first 

 stages passed in the ground. 



How does the mosquito lay its eggs in the water without drowning (176) ? Why 

 are the eggs always laid in still water ? Which part of the larva (wiggletail) is held 

 to the surface in breathing ? What part of the pupa (called tumbler, or bull head) 

 is held to the surface in breathing ? Give differences in larva and pupa. Where 

 does pupa change to perfect insect ? Describe mouth parts of male mosquito (at 

 left) and female (at right). Only female mosquitoes suck blood. Males suck 

 juice of plants. Malarial mosquito alights with hind end of body raised at an 

 angle. For figure see Human Biology, Chap. X. Why does killing fish and frogs 

 increase mosquitoes? i oz. of kerosene for 15 ft. of surface of water, renewed 

 monthly, prevents mosquitoes. 



What is the use to the squash bug (Fig. 184) of having so bad an odor ? 



\ 2 5 <k 5 



FIG. 177. Illustrated Study of Dragon Fly. 3 shows dragon fly laying its 

 eggs in water while poised on wing. Describe the larval form (water tiger). The 

 extensible tongs are the maxillae enlarged. The pupa (i) is active and lives in 

 water. Where does transformation to adult take place (5) ? Why are eyes of 

 adult large ? its legs small ? Compare front and hind wings. 



Do the eyes touch each other ? W T hy is a long abdomen useful in flight ? 

 Why would long feelers be useless ? What is the time of greatest danger in the 

 development of the dragon fly ? What other appropriate name has this insect ? 

 Why should we never kill a dragon fly ? 



