NATURAL ENEMIES. 



31 



a b 



Fig. 9. — Nine-spotted lady-beetle (Coccinella 9-notata): 

 a, Adult; b, L.rva. Much enlarged. (From Chit- 

 tenden.) 



The invertebrate enemies are divided between native species and 

 those imported from Italy, the native being largely predaceous and 

 the foreign all parasitic. 



Besides these, there are two fungous enemies, both of which affect 

 the insect to a greater or less degree. 



Invertebrates . 



When a foreign species, like the alfalfa weevil, is introduced into a 

 new country, some time is required for the native insects to find out 

 that it is suitable for food, pre- 

 cisely as man himself would 

 under the same circumstances 

 have to learn what products 

 of a new country were edible. 

 Besides, he would most likely 

 cultivate a taste for some of 

 these things which at first were 

 distasteful to him. Thus it is 

 that native insect foes of in- 

 troduced species begin slowly 

 at first to prey upon them. 



The following native pre- 

 daceous insects have been found attacking and devouring the alfalfa 

 weevil : 



PREDACEOUS ENEMIES. 



A species of tiger-beetles, Cicindela imperfecta Lee, was in one 

 instance observed to feed upon an alfalfa weevil larva in the field. 



Several other indi- 

 viduals belonging 

 to the same species 

 when taken to the 

 laboratory readily 

 devoured larvae. 



Three species of 

 lady-beetles, Coc- 

 cinella 9-notata, 

 Hbst. (^.g. 9),Hip- 

 podamia spuria 

 Lee, and II. con- 

 vergens Guer. 

 (fig. 10), in the larval stage attacked and devoured half-grown larvae 

 of the alfalfa weevil in the fields. Larvae so taken were brought into 

 the laboratory and adults reared, from which specific determina- 

 tions were made. In case of H. spuria the adult was also observed 

 devouring larvae in the field. 



The malachid beetle, Collops bipunctatus (fig. 11), was repeatedly 

 observed feeding upon the weevil larvae in the fields. 



a b ^ r c 



Fig. 10.— Convergent lady-beetle (Hippodamia convergens): a, Adult; 6, 

 pupa; c, larva. Enlarged. (From Chittenden.) 



