DIVISION OF ENTOMOLOGY. 193 



CAUTION RELATIVE TO IMPORTATION OF FOREIGN INSECTS. 



It will be noted that a great deal of work has been undertaken by 

 this Division during the past year in the importation and distribution 

 of predaeeous and parasitic enemies of destructive insects. A word 

 of caution should be added in this connection. There is danger in 

 the j)romiscuous importation of insects as much as in the case of other 

 animals, and the evidence which we now have would seem to indicate 

 that tlie importation of any insect which is a general feeder on other 

 insects may be a matter of harm rather than benefit; in other words, 

 any general feeder is just as liable to devour beneficial insects as 

 injurious ones, and in this way may do more harm than good. The 

 effort which has been made to artificially hasten the dissemination of 

 the European praying mantis seems to be a case in point. This insect 

 feeds on all sorts of larvae, and, unfortunately, has a very decided 

 liking for our beneficial ladybird larvfe. Importations, therefore, can 

 not be undertaken promiscuously or by j)ersons who are not fully 

 acquainted with the food habits of the imported insects. The intro- 

 ductions in Avhich the Department itself has been interested and for 

 which it is responsible have been in the main of species of limited food 

 habits; in other words, insects which feed only on certain restricted 

 kinds of injurious species, and are not general feeders or general 

 parasites. The benefit to be derived from judicious and intelligent 

 importations may amount to millions of dollars, as has already- been 

 demonstrated in some historical cases in this country. Very great 

 but perhaps not corresponding injuiy may result from unfortunate 

 introductions. It seems, therefore, advisable to make some efl'ort to 

 control such foreign importations bj" having all such work go through 

 the hands or be done with the ad^dce, at least, of this Department. 



THE SOUTH AFRICAN GRASSHOPPER FUNGUS. 



The rej)ort of last year contained an account of the work of this 

 Division with the South African grasshopper fungus throughout the 

 Mississippi Valley and Colorado region in cooperation with the 

 Bureau of Animal Industry. The experiment has been continued 

 the i^resent year and much extended, the intention being to give this 

 fungus a thorough and practical test to demonstrate whether it can 

 really be counted on as a means of controlling the locust or not. As 

 reported by Dr. Howard in the Yearbook of this Department for 1001, 

 the number of experimenters last year during the entire season was 

 223. For this season, at the time of writing only half over, the 

 Division has already sent cultures of the fungus to 886 individuals. 

 This does not include the perhaps even greater number of cultures 

 which have been locally prej^ared by various individuals, and 

 especially by Prof. C. P. Gillette, of the Colorado State Agricultural 

 College, who has taken charge of the culture preparations and their 

 distribution in his State. Very few of the persons to whom cultures 

 have been sent have yet repoi-ted, it being still too early in the season 

 to determine the outcome. These cultures have been sent out to 25 

 different States and Territories, and so far 9 reports of success have 

 been received, 36 of failure, and 821 remaining to be heard from. It 

 is now too early to give definite judgment, but it seems probable that 

 very great reliance can not be placed on this fungous disease. Either 

 it does not work Avith our grasshoppers as readily as it does with the 



AGR 1902 13 



