42 BEES AND BEE-KEEPING. 



occasion this exceedingly beautiful rhythmic move- 

 ment. Those desiring to study it, had better first 

 try the common gentle, its muscles not coming to 

 absolute rest till nearly half an hour after removal 

 from the body. Muscular fibres under a low power 

 of the microscope are easily recognised, on account of 

 their considerable size and striated (cross lined) ap- 

 pearance. They are each covered by a remarkably 

 attenuated membrane, called sarcolemma, in which, 

 generally, a delicate tracheal tube takes its course. 

 Indeed, in the muscles of the wings every fibre has 

 its own particular tracheole (small trachea). The 

 muscular fibres, in this case, lie side by side, and are 

 arranged in bundles (fasciculi) ; across these pass air 

 tubes, parallelly arranged, which give off from their 

 sides these tracheoles at singularly regular intervals, 

 the latter being equal to the diameter of the fibres- 

 Each tracheole then follows the path of the fibre oppo- 

 site to it with the uniformity of the rungs of a ladder. 

 This wonderful structure, like every other, could not 

 be properly examined without making us feel that 

 beauty in Nature is something more than skin deep. 

 Most muscles in the bee are attached direct to some 

 portion of the external skeleton, and, where distant 

 parts are thus to be connected by small muscles, 

 tendons are added, as we see in Fig. 10, which re- 

 presents the apparatus for opening and shutting the 

 jaw ; here all the muscles have tendons, two of 

 which are exceedingly long. The striated fibres are 

 attached to the flattened terminal portion of the 

 latter, and are arranged in a plumose form, as seen 

 in the illustration. 



