XIV 



Mr. Meldola stated, with reference to the imitation of ants by spiders 

 mentioned by Mr. Mansel Weale, that in his belief the remarkably inte- 

 resting cases made known in the present paper could be better explained as 

 instances of aggressive mimicry by the spiders for the purpose of obtaining 

 food. There is no reason to suppose that the ants are themselves free from 

 persecution by insect foes ; thus it would be no advantage to the spiders to 

 resemble them for mere protection. It is stated that the ants visit the trees 

 for the purpose of feeding on the sweet secretions, and that large numbers 

 of flies are attracted with the same object. Now the ants are not predatory 

 on the flies, and can thus mingle with the latter without causing alarm. 

 The spiders by mimicking the ants would thus be enabled to obtain an 

 abundant supply of food, and, not being actually a foe to the ants, would 

 be allowed to live with them on the friendly terms mentioned by the 

 observer. 



Mr. A. H. Swinton communicated a paper " On Display and Dances 

 by Insects." 



Mr. J. W. Slater communicated the following paper : — 



" On the Secondary Sexual Characters of Insects. 



" To prevent any misunderstanding, it may be well to premise that by 

 ' secondary sexual characters ' I mean parts conspicuous in one sex — 

 generally in the male — and either wanting or very slightly developed in 

 the other; but which, at the same time, take no share in the process of 

 reproduction, or at most one quite subsidiary. In many cases, indeed, it is 

 still doubtful whether the parts in question subserve any function at all in 

 the economy of the species. The origin and the purpose of these organs, 

 or portions of organs, has accordingly given scope for much controversy and 

 for a variety of theories. To one of these theories, of recent origin, I wish 

 to direct particular attention. For the sake of convenience the appendages 

 under consideration may be divided into the following classes : — 



Projections of the thorax, above, below, or at the sides. 



Ridges, tubercles, horns or other extensions of the fixed parts of 



the head. 

 Prolongations, enlargements, and complications of the antenuge, 



mandibles, and palpi. 

 Special modifications of the legs. 



" It will be at once obvious that peculiar developments of the two latter 

 classes are much more easily accounted for than those of the two former. 

 Any theory which professes to give an account of the functions of the 

 antennae must be able to explain why these organs are in such a multitude 

 of cases longer and more complicated in the male sex than in the female, 

 whilst the contrary arrangement is, I believe, never met with ; why we find 



