207 



22iid August, 1873. — Dr. Braithwaite in the Chair. 



The minutes of the preceding meeting were read and confirmed. 



The following donations to the Club were announced, viz. : — 

 " Science Gossip" -^ 



" Monthly Microscopical Journal" j ^°^ ^"^^st fromtlie Publisher, 

 " Proceedings of the Geological Association " ,, Association. 



The ballot for new members then took place, and the following gentlemen 

 were duly elected members of the Club: — Mr. William Bartlett, Cambridge 

 Villa, Southall; Mr. S. Israel, No. 1, The Crescent, America Square. 



The President announced that there was no paper for this evening, but that 

 Mr. Lowne had kindly volunteered to make a few observations on " The Mouth 

 Organs of Insects." 



Mr. Lowne said that previous to his coming into the room he had no idea that 

 he would be asked to fill up the gap caused by the want of a regular paper, and 

 that it was only fair he should make that statement, as entitling him to the 

 consideration of the meeting for the unprepared condition in which he addressed 

 them. He proposed to offer a few observations respecting the Mouths of Insects, 

 which, as we all knew, were favourite objects, considerable portions of our 

 cabinets being filled with them, and although the subject was not a very novel 

 one, yet he hoped that he might be able to put it more fully before the members 

 than was commonly done in works of an elementary nature, and more clearly 

 than in those of a more portentous character. 



If we take the mouth of any large beetle, we find all the parts easy to recog- 

 nise, with the additional advantage that all the structures are the same rela- 

 tively as in the most modified mouths, even of those modified for special pur- 

 poses. The use, in other words, may be different, but the parts are the same 

 though not always easy to recognise as such. There is nothing, for instance, in 

 a fly's mouth, which does not exist, in a plainer condition, in tlie mouth of a 

 beetle. If we take a Stag-beetle, we observe first the large horns, which are the 

 mandibles or jaws of the insect. We observe next that these work laterally, 

 not vertically, as in the case of mammalia, &c., and this is the case with all 

 insects. Above the mouth we find a plate, forming the roof of the mouth, and 

 imderneath another plate forming the floor of the mouth ; both of these lie 

 parallel with each other. The mandibles, like those of all other insects, are 

 hollow, and are moved by very powerful muscles. Whether they are in this case 

 used for procuring food, or are simply ornaments, the speaker could not under- 

 take to say. In the instance of the Stag-beetle, the mandibles are comparatively 

 feeble in proportion to the size of the insect, but in others they were frequently 

 of great strength. In a little space, under these mandibles, there are two jaws, 

 which also move parallel to the roof and floor of the mouth ; these are the 

 maxillcB, which are sometimes cutting organs, and occasionally more developed 

 than the mandibles. We now see that, as far as we have gone, the main parts 

 of the mouth are — 



The upper lip, or lahrum. 



The lower lip, or labium. 



The mandibles. 



The maxillae. 



If wo now take a magnifying glass, we find another organ called the ligula or 



tongue, sprin(;ing from the floor of the mouth, the same as in the higher 



animals. This organ is much modified in different insects, as for instance in 



bees, which have about 300 joints. The general use of the tongue of a bee is 



