BUREAU OP ENTOMOLOGY. 225 



be secured continued and severe injury is likely to result. *L special 

 investigation of this insect is in progress. 



The chinch bug. — No severe general outbreak of the chinch bug 

 has developed during the year, although infestations of local im- 

 portance occurred, especially in Oklahoma and Kansas. It was 

 found that soap solutions were effective in killing the young bugs, 

 but did not control adults. Experiments in control of this pest on 

 St. Augustine grass in Florida indicate the possibility of success with 

 contact insecticides. An effort is being made to improve the ditching 

 and barrier methods of control in the Middle West. 



White grubs. — As predicted by the bureau, a white-grub outbreak 

 of great severity and magnitude occurred during the year in the 

 States of Iowa, Illinois, Wisconsin, Michigan, Indiana, Ohio, Penn- 

 sylvania, New York, New Jersey, and Connecticut. Warnings were 

 issued through the Office of Information of the Department of Agri- 

 culture and through the public press. Progress has been made 

 toward the determination of the extent of the various destructive 

 broods of white grubs. Life histories of many species are now 

 known, and the distribution of the species is being accurately de- 

 termined. 



The fall army worm and the true army worm. — During the 

 autumn of 1915 the fall army worm became numerous in the South- 

 western States, and was responsible for considerable injury to kafir, 

 late corn, and winter wheat in portions of Oklahoma, Texas, and 

 Nebraska. It appeared also in the Salt Kiver Valley in Arizona, 

 where it assumed the habit of boring into the nearly mature ears 

 of corn in precisely the same manner as the corn-ear worm. This 

 pest has reappeared this season in Oklahoma, and further injury 

 may be done before fall. A new publication dealing with the con- 

 trol of this insect is in the press, and an effort is being made to 

 colonize in Florida, by introduction from New England, a parasitic 

 fly which is an important enemy of the gipsy-moth caterpillars. 

 Two thousand puparia of this fly have been collected in Massachu- 

 setts and shipped to Gainesville, Fla., for rearing and liberation in 

 that State so that it can be colonized in numbers, and it is hoped that 

 its work upon the early spring generation of the pest will prevent 

 rapid multiplication and migration. 



No important outbreak of the true army worm developed during 

 the year, although the moth was present during the summer of 1916 

 in the Atlantic States. A new and fully illustrated farmers' bulletin 

 dealing with it has been issued recently. 



Wireworms. — Studies of the injurious wireworms have been con- 

 tinued. The effect of tile drainage of fields infested by certain 

 species is being investigated, and fumigation of the soil with hydro- 

 cyanic-acid gas evolved from sodium cyanid, and with other insecti- 

 cidal substances, is being tried. 



Alfalfa seed chalcis. — An effort has been made to determine the 

 extent of injury by this pest to crops maturing during the different 

 seasons of the year on the Pacific slope. The present loss by this 

 insect to the alfalfa seed crop is estimated at about 30 per cent of all 

 the seed grown in the United States. In the case of some late crops 



