( cxxviii ) 



tlian an endeavour, an impevfect one, to follow out thoughts 

 suggested in that address, and to test or illustrate their 

 application to some of the questions which arise. 



Professor Meldola asks these questions — "Are the external, 

 visible, appreciable, measurable characters alone to be regarded 

 as of selection value 1 May not some at least of the minor more 

 or less constant specific characters be the outward expression 

 of some constitutional or physiological differences at present 

 beyond the power of our methods of discrimination 1 " Among 

 the qualities or characters which may thus be of selection 

 value Professor Meldola proceeds to mention habits, of which 

 he says that " they are not and cannot be taken into considera- 

 tion in ordinary diagnostic work. Nevertheless, such habits 

 are as truly specific as the form, colour, and pattern with which 

 they are associated." * 



Examples of inarhed differences of habit. 



We may conveniently enumerate here some habits and 

 actions of insects that are special to certain groups of them, 

 large or small, including such as are chai-acteristic of the 

 individuals of a species or even variety, and, in connexion 

 with this subject, we may perhaps usefully consider whether 

 they or some of them may not be of biological importance. 



First let me give a few examples of differences of habit 

 which fall under the observation of every field naturalist, 

 some of them being of a very marked character.f 



Modes of flight. 

 There is the slow heavy flight of the burnets (Anthrocerids) 

 and of some nocturnal moths, especially their females ; these 

 become easy victims to their pursuers, but are often protected 

 by nauseousness from pursuit. Few Lepidoptera have a straight 

 flight, most have a more or less jerky one, some in long curves, 

 some in shorter ones, and many have the zigzag flight of the 

 common white butterflies, including females of some species, 

 the males of which fly with more rapidity and directness, this 



* Proc. Ent. Soc. Loud. 1896, pp. 69, 74. 



i There is a great fund of iiit'ormatiou on this subject iu tlie " British 

 Lepidoptera " of that excellent field observer, the late Charles Barrett, 

 also in Mr. Tutt's "Practical Hints for Field Lepidopterists." In these 

 works a great variety of habits will be found recorded, ilany pages are 

 also devoted to them in Scudder's "Butterflies of North America." 



