c. PRESIDENT'S ADDRESS. 



migrations of various beetles. For instance, Buenos Ayres 

 was visited in two consecutive springs by swarms of Harpalus 

 cupripennis, which arrived at dawn for eight days in succession, 

 and had to be swept away every morning from the outside of the 

 houses, where they were (so it is stated) piled up to a height of 

 several feet. 



DlPTERA. 



The genus Syrphus seems perhaps, amongst the Diptera or 

 flies, to be that most given to migration, at all events in this 

 country, and there are various records of great swarms observed 

 in different places. Some of these are, no doubt, connected 

 with the movements of Aphides, but others do not seem to be so 

 accounted for. There are one or two records from Dorset, 

 which may be interesting here, one being of a swarm of Syrphus 

 pyrastri, at Bournemouth in August, 1869, and of a line of their 

 dead bodies extending from Poole Harbour to Christchurch Bay 

 along the seashore. Another record speaks of their abundance 

 in the Bridport neighbourhood about the same time, and the 

 same swarm seems to have visited Eastbourne and the Isle of 

 Wight, and must have been of great magnitude. 



The assembling of flies in houses for the purpose of hiber- 

 nating sometimes takes place on a large scale. In a house I 

 know which stands near a farmyard, where the flies, chiefly of 

 the genus Musca, are doubtless bred, vast numbers enter in this 

 way and form quite a plague, which it seems hopeless to contend 

 against. Everyone knows the determined manner in which gnats 

 and certain other flies will follow their victims, either oneself or 

 a horse or other animal, for long distances, dancing in clouds 

 round them ; and this would constitute a kind of migration, for 

 one can scarcely imagine that the flies would return by them- 

 selves after having journeyed perhaps several miles. One of the 

 most remarkable fly migrations is that of the larvae of Sciara 

 militaris, in which vast numbers of these legless grubs, about 

 inch long, join together by their sticky skins, so as to form a 



