INSECT VARIETY. 63 



Vitis Graber^ place the sense in tlie cavity of the mouth ; and 

 Christian considers insects exercise it in relation to distant 

 objects through their antennse, and in regard to near ones by 

 adaptation of their palpi. However, the primary function of the 

 antennae and palpi is pre-emineutly that of touch, especially in 

 terrestrial locomotion ; and it has been inferred that these organs 

 direct the flight in species likewise aerial, on account of the 

 ii-regular path described by such insects when deprived of them, 

 as might occur by their being adapted to receive impressions of 

 odours, attractions, vibration, or radiation. 



But as has been remarked they probably serve some further 

 intent than touch, for their shortness in Hies and Cicadse does not 

 accord with that usage. But apart from their employment, 

 naturalists came to attribute to them a sense corresponding 

 to smell or hearing, and up to the date of the discovery by 

 Miiller, in 1829, of organs of greater structural adaptation for 

 the latter function, opinion on this topic ran even. Since that 

 period the idea has become more prevalent that they are organs 

 of smell, and it is certain insects employ them when searching 

 for nectar, and some which deposit on odoriferous matter have 

 them well developed. I conceive it also a fact that it is in kinds 

 which fly rapidly among obstructions in search of food that 

 we notice these parts lengthened, pectinated, or lamellated. 

 In the beetles, for example, the antennae become prolonged 

 in the Longicornes, serrated in the Serricornes, clubbed like 

 those of a butterfly in the Clavicornes, Weevils, and Short 

 Elytras, and leaved or lamellated in the Lamellicornes. 

 In the scavenger ground beetles and lowly leaf-feedei's they 

 are generally simple. In this case we find the club and 

 leaved adaptations confined to vagrant species that live on 

 excrement, flowers, or sap, and the serrated form in those 

 of various habit. The species also that present dilatation or 

 extension of the antennae often employ these organs in a manner 

 to suggest adaptation for scent. The Rose Beetle of our gardens 

 when presented with flowers, according to Mr. Slater, erects its 

 antennae and opens the leaflets of the club ; and Sulzer remarks 

 when lamellicorn beetles settle on blossoms they alternately open 

 and shut the leaflets of their antennae. The Longhorns employ 

 them as tactors, and thus track the female at the pairing season. 



