USEFUL INSECTS 5 



lination of flowers. Bumblebees perform a notable 

 service in cross-pollinating clover/^ 



The Blastophaga, a minute wasp-like insect, 

 cross-pollinates the cultivated and wild fig, thus 

 making possible the production of the Smyrna fig 

 in California/^ 



PREDACEOUS INSECTS 



Many species of insects catch and devour other 

 species for food. These are known as predaceous 

 insects and they are of immense value in aiding 

 man in the fight against his insect foes.^^ 



The ladybird beetles are probably the most impor- 

 tant. There are several species, the two-spotted 

 ladybird (Adalia bipunctata), the twice stabbed 

 ladybird (Chilocorus bivulnents), the convergent 

 ladybird (Hippodaniia convcrgens), and other spe- 

 cies. 



Many larvae of a family of flies, the Syrphidce, 

 perform great benefit in destroying plant lice. 



The ground-beetles (Carabidcu) are exceedingly 

 beneficial in destroying insects that are found upon 

 or in the soil. 



Other beetles, flies, wasps, and certain bugs, con- 

 tribute to the good work. 



PARASITIC INSECTS 



There are many insects that live upon or within 

 the eggs or bodies of other insects and derive the 

 nourishment necessary for their growth from their 

 living hosts. These are called parasitic insects and 

 are among the best natural checks of insect pests. ^^ 



10 Waldron— Report of North Dakota Sub-Expt. Sta., at Dickin- 

 son, 1908. 



11 Howard — U. S. Dept. Agri., Yearbook 1900, p. 79. 



12 Smith — Insect Friends and Foes. 



^3 Webster — U. S. Dept. Agri., Yearbook for 1907, p. 237. 



