PRESIDENT $ ADDRESS. 3 



In very many cases, by breeding and otherwise, it has been 

 shown that some species vary in an extraordinary degree, 

 so that one hardly gets two specimens exactly alike. It*has 

 lately been shewn from a long series of Rhizopods dredged 

 in the N. Sea and N. Atlantic that a number of forms, hitherto 

 classed as species under two genera, are all varieties of one 

 species, Thurammina papillata, Brady. Luminous earth- 

 worms have been observed in S. Africa on Table Mountain, 

 the light proceeding from a viscid substance emitted by the 

 worm. I think that a similar phenomenon has been seen in 

 England ; but I am not sure of this. Some curious experi- 

 ments have been made in training water-snails. Food is 

 presented to the snail, which causes it to move its mouth 

 parts, and its body is at the same time touched with a rod. 

 After 48 hours training (whether continuous or not is not 

 stated) the snail responds in the same way to the rod alone ; 

 but after a period of 96 hours or less it ceases to respond, 

 having by that time unlearnt its lesson, and discovered that 

 the rod does not mean food. A plague of moths (Char was 

 graminis) appeared last year from Cumberland to Derby- 

 shire ; but, though in enormous numbers, the larvae confined 

 their depredations to bent grass ( Nardus stricta), and there- 

 fore did little damage. The Isle of Wight disease has been 

 most destructive of late years amongst honeybees ; and in 

 my own neighbourhood, as in many others, they have been so 

 scarce that hardly a bee has been seen in my garden, except 

 some recently imported Ligurians, distinguished by their 

 banded bodies. There seems still to be some uncertainty 

 as to the cause of this disease and its nature, the bacillus, 

 Nosema apis, usually considered as a necessary accompani- 

 ment of it, being often absent in apparent cases of it. leery a 

 Purchasi, a sort of scale insect, a native of Australia, which 

 does much damage to orange trees, has spread to other parts 

 of the world, such as Ceylon and N. America. An entomolo- 

 gist sent by the Government to Australia has brought back 

 to California a number of ladybirds, which have been most 

 effectual in destroying the pest. Earwigs seem not to be 



