394 DR. J- B. HICKS ON THE ORGANS 



where the antennae of the Pedictilus of the Crow are represented. Two organs are found 

 on each joint, except the last two. In the Fediculm of the Dog the organs are very 

 large ; they are shown in profile at V. fig. 1 b. 



Fiilex also has them on each joint, as seen at V. fig. 2. An enlarged view of those of 

 the Fulex of the Mouse is shown in fig. 3. 



Having now detailed all the principal facts I have been able to secure since my last 

 paper, I shall again endeavour to point out the great advantage to be derived from the 

 process of bleaching which I described at that time, without which it would have been 

 impossible, by reason of the depth of colour of the insect-integument, to have made such 

 advances upon our previous knowledge. It is for this reason that I have no doubt the 

 opinions of the naturalists I mentioned at the beginning of this communication would 

 have been different, had they known the precise nature of the organs behind the closed 

 pores ; for it does seem to me impossible that the essential nature of an olfactory organ 

 should be included in the structm-es just mentioned, and that odorous particles could 

 pass, fii'st through a membrane, sometimes even spinous, then through a cavity filled 

 with fluid, and thirdly through another membrane to reach the extremity of a nerve. 

 On the other hand, it is not difficult to conceive that such a structure would be well 

 suited to the transmission of sound, upon the principles jiointed out by Miiller ; and the 

 numerous modifications of these antennal organs especially to be found in the Hymeno- 

 ptera, seem to form an additional reason for supposing them to be auditory — namely, 

 that they may give the insects a power of appreciating sounds of various pitch. 



Amongst entomologists, some misconception as to the nature of the antennse has 

 arisen from their not duly considering, in their observations on the habits of insects, that 

 the antenna has (whatever other function it possesses), in a great number of insects, a 

 faculty of feeling superadded, at least in those insects whose antemise are tolerably mobile. 

 There can be no doubt that most of the Hymenoptera use them as tactile organs ; and I 

 am sui-e that the Honey-bee, Andrena, and the Ichnemnonidce do so continually, though 

 most writers have considered that the numerous movements of the antennae of the Ich- 

 neumons are for the purpose of smelling ; but I am confident that strict observation 

 would confirm my opinion that these motions are for feeling — and thus to enable the 

 Insects to detect the opening of the holes in which the larvse they are seeking reside ; 

 and that the antenna could be used as well for hearing any noise the larvse made, as for 

 smeUing out their position. The Ant has been quoted as an instance strongly showing 

 that the antennae are used for smeUing, as is manifested in the power of mutual recogni- 

 tion possessed by these Insects. Last summer I had opportunities of observing the 

 Wood-ant ; and found that it invariably acted in the following manner when two indivi- 

 duals met one another from opposite dii-ections : — Fii'st, they approached and brought 

 their antennae into contact for a moment ; then, approaching nearer, they brought their 

 palpi together, and retained them in contact during the whole time, whilst the antennae 

 never touched each other again. By what means they communicated their thoughts it is 

 impossible to say ; but I suspect the palpi played the most important part. 



Erom the various remarks made in this paper, as well as from the observations of 



