Ixii. PRESIDENT'S ADDRESS. 



in different seasons are generally very obscure, which gives 

 importance to observations in the Lake district proving that 

 the numbers of a sawfly destructive to larch were immensely 

 reduced on two occasions by sudden increases in three 

 parasites hitherto almost or quite unknown. This supports 

 the method, sometimes successfully carried out, of introduc- 

 ing suitable parasites to a district subjected to any pests. 

 The most effective device for destroying locusts in the Sudan 

 is said to be the sprinkling of poison mixed with treacle on 

 the herbage, which would, however, one would think, be 

 most dangerous to animals. One of the most cleverly worked 

 out histories of the habits of insects is that on the courtship 

 of the Empid flies, lately published by Mr. Hamm. These 

 flies, of which there are numerous species, have a long proboscis 

 with which they transfix other insects and suck their juices. 

 When a male approaches a female he brings with him an 

 offering, which varies in different groups. In one it is an 

 insect, which is received by the female, which sucks it during 

 pairing. In another group a stamen or other fragment of a 

 flower or insect is offered, with which the female merely plays. 

 In another the male spins a cocoon round some small body, 

 which cocoon is accepted by the female. There are many 

 other details of these unique proceedings, into which space 

 will not permit me to enter here. A great deal has been 

 spoken and written lately on bird protection, and some 

 countries, as the U.S.A., have made laws affecting the welfare 

 not only of their own birds, but of those of other countries, 

 by prohibiting the importation of the skins of plumage birds, 

 and I believe that England is likely to follow their example. 

 In the case of species that are recklessly destroyed or 

 threatened with extermination, I think such drastic measures 

 are justified and desirable if, as seems probable, it is difficult 

 or impossible to enforce protective laws in the countries 

 where the birds live. As far as I know, most of these fine 

 plumaged birds are harmless, and some of them perhaps 

 useful to man. But if ladies are chiefly responsible for the 

 slaughter of these beautiful birds, men on the other hand 



