78 



633a. OYSTER SHELL BARK-LOUSE. 



Mytilaspis pomorum. 

 Infested Apple Twig. 



This model represents a twig of apple, the older parts of which are 

 thickly infested with the Oyster-shell Scale. 



634. POTATO PLANT. 



Solanum tuberosum. 

 A model in wax of a healthy potato plant is shown in this exhibit to 

 contrast with an adjoining model, which illustrates the injury done by 

 the principal potato pest, the Colorado Potato Beetle, Doryphora deccm- 

 lineata. 



635. POTATO PLANT.. 



Solanum tuberosum. 



A model of a potato plant is shown, representing the injury arising 

 from the attacks of the principal enemy of the potato, the Colorado 

 Potato Beetle, Doryphora decemlineata. The beetles are shown in nat- 

 ural position on the defoliated plant, with the larvae, and also a number 

 of their principal insect enemies, such as predaceous bugs, robber flies, 

 tiger and grouud beetles, which attack and destroy the larvae and eggs. 

 A complete collection of the principal insect enemies of the potato is 

 shown in the regular economic exhibit. (See No. 584.) 



636. TOMATO PLANT. 



Lycopersicum esculentum. 

 The wax model of the tomato plant illustrates the work of the Tomato 

 Worm, Protoparce celens. Wax models of the larvae are shown in nat- 

 ural positions on the plant. (See No. 528.) 



637. CURRANT. 



Kibes sp. 



The wax model of a currant branch illustrates the work of the Im- 

 ported Currant Worm, Nematus ventricosus. For extended exhibit of 

 the insects affecting the currant see regular economic exhibit. (See 



No. 117.) 



638. PLUM CURCULIO. 



Conotrachelus nenuphar. 



The work of the Plum Curculio on the fruit of the plum, apple, pear, 

 cherry, and peach is illustrated by special models. For full details as 

 to the work of this insect see exhibits in regular economic series. 



639. PLUM CURCULIO. 



Conotrachelus nenuphar. 



Young apples, showing the effects of puncture by the female Curculio. 

 (See No. 31.) 



640. PLUM CURCULIO. 



Conotrachelus nenuphar. 



Young pears, showing effect of puncture by the female Curculio. 



