THE CANADIAN ENTOMOLOGIST. 183 



AN EXPERIMENT IN THE IMPORTATION OF BENEFICIAL 



INSECTS. 



BY F. M. WEBSTER, WOOSTER, OHIO. 



In the February number of the Canadian Entomologist I gave the 

 results of an experiment in the exportation of a few of our native lady 

 beetles to South Africa. I now have the pleasure of giving the result of 

 an experiment in the importation of some South African lady beetles. 



March 27th, Mr. C. W. Mally, Assistant Government Entomologist, 

 sent me several specimens of Exochomtis nigromacu/atus, and quite a large 

 number of two smaller, unnamed species. All of these attack more espe- 

 cially the Mealy bug, Dacty/opius, in their native home. The consignment 

 was made by simply fastening twigs of Oleander very badly affected with 

 Mealy bug, to the bottom of the box, and putting the lady beetles among 

 them. The package reached me April 23rd, and, strangely enough, there 

 were but very few of the specimens that were not alive and active. The 

 importation was thus an entire success. Mr. Mally writes me that, about 

 Cape Town, these lady beetles are kept considerably reduced in numbers 

 by a small Hymenopterous parasite. In releasing the lady beetles, we took 

 precautions not to allow these parasites to escape, so that the insect, if it 

 secures a foothold in this country and stands the climate, will have no 

 natural enemies to hold it in check. In cases like this, and more 

 especially in the one previously recorded, any permanent establishment of 

 these insects would be to a certain extent accidental; that is, in the former 

 case the lady beetles were not sent out to prey upon an insect in South 

 Africa, whose original home was in America. In the present instance these 

 lady beetles will probably destroy the Mealy bugs in conservatories, but 

 it is yet to be determined whether they can withstand the rigours of our 

 northern climate in the open. Very many injurious species are introduced 

 and become established in this country through pure accident, and it 

 would seem that we might expect an occasional instance of this kind to 

 occur among beneficial insects intentionally introduced; but the principal 

 motive in these two transactions has been, not so much with a view of 

 colonizing these insects in the respective countries, as to secure informa- 

 tion that would be of service to us in future transactions of this kind. 



These experiments cost practically nothing, and through them we 

 shall be able to get a better idea of the best methods of sending beneficial 

 insects from one country to another, so that when an opportunity does 



