INSECT PESTS 167 



main to be investigated. The develop- 

 ment of Empusa aphidis depends upon 

 rather warm, humid weather for its spread 

 and is retarded by drought. This fungus 

 was found fairly active during the sum- 

 mer of 1912. It is possible to cultivate 

 the fungus artificially and it may be used 

 to inoculate broadcast the aphids in the 

 field. 



THE TWELVE-SPOTTED CUCUMBER BEETLE 



Diabrotica 12 punctata Oliv. 



The larva of this insect feeds on roots 

 and stalks of corn and on a number of 

 other plants but as far as is known does not 

 feed on roots and stems of sweet peas. It 

 is the adult beetle of this insect that is 

 troublesome to outdoor sweet peas. The 

 beetle is one of the earliest pests seen to 

 feed on the plants, as soon indeed as they 

 are no more than six inches high. The in- 



