USES OF THE ANTENNAE. 193 



species, and after having laid its eggs it generally lies down 

 and dies. 



The jointed antennae of the innumerable insect tribes exhibit 

 a wonderful diversity of form ; now drawn out into a thread, 

 and now ending in a knob now pectinated like a comb, and now 

 expanding like a fan. We find them smooth or hairy, simple 

 or divided into branches, projecting or recurved sometimes 

 short, sometimes of a length far surpassing that of the body. 

 When the insect is in motion, they are stretched out and ex- 

 panded to their fullest extent; but by many species they are im- 

 mediately retracted on the occurrence of any loud or sudden noise 

 and then there is in many cases a channel or groove ready to 

 receive, to hide, and to protect them against many injuries. 



That organs so beautifully constructed and so carefully pro- 

 vided for, must necessarily be of the highest importance, is 

 evident ; but strange to say, their use has not yet been fully 

 ascertained. The late Professor Erichson of Berlin discovered 

 their solid case to be perforated by a number of little holes lined 

 internally with a delicate membrane; and as the air can thus 

 easily penetrate into their cavity, this distinguished entomologist 

 considered their function to be that of smelling. Others, again, 

 are of opinion that they are auditory organs, and in many cases 

 there can be no doubt that their office is that of touching or 

 feeling other objects. Thus the honey-bee when constructing 

 its cells ascertains their proper direction and size by means of 

 the extremities of its antennaB, while the same insect, when 

 evidently affected by sounds, keeps them motionless in one 

 direction as if in the act of listening. 



Wherever the sense of smelling in insects may reside, there can 

 be no doubt of its exquisite acuteness, particularly in those species 

 that live on decayed or putrid animal substances, and occupy a 

 high rank among the scavengers of Nature. Scarcely does a sub- 

 stance answering their wants drop to the ground, than the dung- 

 beeties are seen hurrying along from distances proportionally 

 as remarkable as the vast spaces measured by the vulture's eye. 

 A loud and joyous hum accompanies their active flight, which 

 in strength and duration, surpasses that of all other beetles, and 

 materially assists them in the performance of their useful labours. 



Sir Emerson Tennent was once present at the death of an 

 elephant, and saw how the flies, of which not one was visible 



