XVlll 



On the Exinession of the Emotions by Insects. By A. H. Swinton. 

 (Read March 6th, 1878.) 



Lamarck, as is known, defined Insecta as sentient animals that obtain 

 from their sensations perceptions only of objects, simple ideas they are 

 unable to combine to form complex ones, which more intelligent animals 

 not only do, but retain notions thus formed. Since the promulgation of this 

 definition, deeper insight has been gained by the investigations of De Geer, 

 John Hunter, the Hubers, Kirby, J. Rennie, Burmeister, Goureau, Miiller, 

 Siebold, Westring, Landois, and others, as may be seen in the masterly 

 resume by Darwin and his coadjutors (' Descent of Man,' vol. i., chap, x.) 

 The fuller development and partial localisation of the sensorial organs 

 of touch, taste, smell and sight in larvae, and of hearing in imagos, having 

 reacted on the nervous system, has led to the production of emotions 

 cognate with the passions, such as fear, love, rivalry, and maternal care. 

 The intensity of these stimuli is indicated by contractions, secretions, 

 battles, display, and dances, vocal and instrumental music, wing beating, or 

 (in the perfect state) migrations. 



Simple muscular contractions indicative of fear are evinced by larvae, 

 pupae, and perfect insects, and may result from touch, taste, sight, or 

 hearing. Thus, when touched, larvae contract or roll up, and certain pupae 

 wriggle. Many Coleoptera on touch turn lethargic, forcibly contracting 

 their legs and antennae. This is characteristic of hemispherical kinds, 

 such as Byrrhus, Rhyncophora, Coprinidce, and Phytophaga ; also of 

 elongate species, such as the Elateridce. Some also depress their heads 

 slightly (Necrophaga), or withdraw them into grooves {Curculionidce). 

 Others, instead of contracting the legs, rigidly extend them when alarmed 

 [Geotrupes stercorariiis), or, porrecting the anterior, contract the hind legs 

 {Geotrupes Icevigatus) ; others again partially withdraw them on alarm 

 (Geodephaga), while the Eucmiidd under these circumstances stand paralysed, 

 gaping with their mandibles. Hemiptera and many Neuroptera, on touch, 

 similarly contract their limbs, the latter with many Lepidoptera retaining 

 their wings motionless. Among Hymenoptera, ChrysldidcB, on seizure, 

 convolute the abdomen, while others turning on their back extend the 

 intermediate legs. These spasmodic symptoms not uncommonly result 

 from sight or hearing. Thus lepidopterous caterpillars jerk the head to 

 a passing cloud-shadow (Ca/Zmor/j/ia), and I remember even on approaching 

 a minute coleopteron near London, that its limbs contracted, and it fell 

 down before I could reach it. Many species of Lepidoptera similarly elude 

 the collector. 



Muscular contractions on touch or siglit, accompanied by an emission of 



