Nov. 15, 1911 



THE MUSCLES OF THE HONEY-BEE. 



BY DR. BRUENNICH. 



68T 



One of the most important characteristics 

 that distinguish the vegetable kingdom from 

 the animal is voluntary movement; and 

 only in the case of the lowest organisms is 

 it true that this difference will not stand the 

 test, there being a great many forms of bac- 

 teria which can not be counted in the ani- 

 mal kingdom, but yet which possess the 

 power of locomotion. 



Movement in the lower animals is pos- 

 sible because of organs called muscles. While 

 a common type of structure is evident in 

 the whole animal kingdom, there is consid- 

 erable difference in the development of par- 

 ticular classes of muscles. For instance, the 

 vertebrates possess for involuntary move- 

 ments (intestines, arteries, etc.) , the smooth 

 muscles, these being but cells of an inferior 

 development; and for voluntary movements 

 the well-known striate muscles, these being 

 animal cells of a very high degree of evolu- 

 tion. 



Fig. 1. — Sting of bee, show ms muscles. 1. 2. spear 

 and husk: 3, 4, retractor of speai: 5, protractor 

 of spear; (J, oblong plate: ^ , triangular plate: 

 ■ , square plate. 



It is remarkable that bees and kindred in- 

 sects possess two kinds of muscles which 

 are very difTerent from each other. To name 

 them according to their structure, for the 

 sake of simplicity and a better understand- 

 of them, I will call them tube muscles and 

 fascicle muscles. The first are found every- 

 where in the body of the bee; the latter are 

 found associated in the breast of the bee, 

 forming there the muscles of flight. JJoth 

 muscles assist in voluntary movements. 

 The discovery of involuntary muscles has 

 not yet been effected. 



Let us look first at the more frequent tube 

 muscles. Unlike the flight muscles, these 

 exist as single fibers, often united in groups, 

 however, where each fiber seems to possess 

 a certain independence. In Fig. 1, the pho- 

 to of a sting, one recognizes a great number 

 of those slender fibers, here united in loose 

 bundles. Each fiber consists of a hollow 

 cylinder of minute diameter. An extreme- 



FiG. 2. — Tubular muscle — fibrils: n, nuclei; s, sar- 

 colemm. 



ly minute canal is trenching the fiber 

 throughout its length. It is filled with pro- 

 toplasm, and with thousands of nuclei side 

 by side, forming a string of pearls (Fig. 2) . 

 The structure of the fiber is an intricate one. 

 In Fig. 3 one recognizes at the first glance 

 a distinct transverse streaking, even visible 

 in Fig. 1, which is not so highly magnified. 

 This striation is a result of the alternation 

 of tiny sheaves of apparently dark and light 

 color; i. e., of greater or lesser refraction. 

 Every dark sheaf with half of the adjacent 

 light sheaf contains a nucleus, and forms a 

 primary sheaf, and it is clear that this little 

 foundation is a unity, a highly develoijed 

 cell. The proof of this assertion is evident 

 when looking at Fig. 2 or the schematic Fig. 

 4; for every primary sheaf is enveloped in a 

 fine membrane, the sarcolemm. But the 

 finer structure of the little sheaves is still 

 more complex, for every fiber shows, besides 

 the t-a verse striation, a distinct longitudinal 

 striation. Figs. 2, 3. This striation is due 

 to the fact that every sheaf is composed of 



Fig. 3.— Tubular muscle. 



