1909 



GLEANINGS IN BEE CULTURE 



501 



cheas become exceedingly fine hollow 

 threads, by means of the ends of which is 

 accomplished the exchange of gases of the 

 body cells, such as the cells of the brain, 

 muscles, intestines, etc. Fig. 1 shows these 

 delicate ends on the vessels of Malpighi. In 

 spite of the considerable magnifying, the ex- 

 treme ends of these tracheas can not be seen 

 on account of their transparency and minute- 

 ness. Nevertheless, the picture gives an idea 

 of the exceedingly fine sub-divisions of the 

 tracheal system. 



As to the construction of the tracheas, it is 

 well known that, in the walls of those little 

 tubes, there are thin spiral threads of chitin 

 which prevent the collapsing of the tubes. 

 .\ compression of the tracheas is not likely; 

 but a certain expansion of them is very prob- 

 able. Fig. 2 shows nicely some larger tra- 

 cheas where the chitinous spires are easily 

 visible. 



Just as the birds have large air-spaces in 

 their bones, so we find, interwoven in the 

 tracheas, air-bags A trachea suddenly wi- 

 dens to a sac of different form, and from this 

 sac different tracheas generally spring. The 

 clothing of these air-sacs contains, like the 

 tracheas, parallel wands of chitin. There 

 are a great number of these air-sacs in the 

 whole body, even in the feet. These sacs 

 diminish considerably the specific weight of 

 the bee's body, and facilitate flying. Second- 

 ly, they serve as air-vessels which prevent 

 excessive pressure in the most minute ends 

 of the tracheas. Thirdly, they serve as air- 

 vessels for reserve. 



When we speak of the mechanism of the 

 respiration we must distinguish between the 

 thoracal and abdominal respiration. It is 

 very probable that the flying bee respires 

 only with the breast, while the bee which is 

 resting or walking uses only the abdomen. 

 Before the bee flies it fills the air-sacs of the 

 abdomen with fresh air — firstly, for lighten- 

 ing the body; and, secondly, for having some 

 reserve in the abdomen, because it is not 

 probable that the latter is respiring in flight; 

 and abdominal respiration, indeed, is not 

 necessary during flight, for the gas exchange 

 takes place during ilight principally in the 

 flight muscles and in the head, which gets 

 its air directly from the breast. The flight 

 muscles, of course, consume much oxygen 

 and secrete much carbonic-acid gas, the me- 

 chanical labor of the wings being very no- 

 ticeable. 



The air-sacs of the breast are of inferior 

 size, for, indeed, large air-sacs here would 

 be in the way, hindering a quick exchange of 

 gas for the flight; the muscles lifting the 

 wings and those lowering them contract al- 

 ternately and energetically. By a certain 

 compressibility of a part of the breast the in- 

 ner room is alternately enlarged and dimin- 

 ished, so that the air rushes in and out, ac- 

 cording to the rhythm of the class (two or 

 three nundred a second). The movement 

 of the wings and the respiration are thus 

 closely together, being produced by the same 

 muscles. 



If a bee rests after a long flight, an ener- 



getic abdominal respiration begins in order 

 to remove the carbonic-acid gas which has 

 accumulated in the abdomen. While the 

 thoracal respiration ventilates only the breast 

 and head, the abdominal respiration performs 

 the exchange of gas in the whole body, where- 

 as the valves of the air-holes of the breast 

 may be working rhythmically. 



The six double segments of the abdonipn 

 slide over one another like the parts of a 

 telescope, and are movable by muscles, so 

 that the capacity can be changed voluntarily 

 by the bee. We know that the filling of the 

 honey-sac or chyle stomach or rectum has a 

 strong bearing on the size of the abdomen. 

 Still more is this the case if all the air-sacs 

 are filled with air. When the bee expands 

 its abdomen, the air-valves, being wide open, 

 the air-sacs are filled by degrees with air; 

 then before the abdomen is contracted again 

 the eighteen valves are closed so that, when 

 the contraction occurs, the air is driven into 

 the finest branches of the bronchial system 

 of the whole body. As soon as part of the 

 valves (for example, those of the thorax) are 

 opened, the tension is lessened by the stream- 

 ing-out of the air; and when the abdomen is 

 contracted to its smallest size, all the air, 

 which before rushed in, is driven out, and 

 thus the brochial system of the whole body 

 is periodically provided with fresh air. 



Ottenbach, Zurich, Switzerland. 



UGLY BEES. 



How Their Temper Varies According to 



the Source from Which They 



Gather Nectar. 



BY LESLIE BURR. 



Mr. Root:— Your editorial about the bees 

 being so cross during the flow of horey-dew, 

 and the reason you and Mr. Vernon Burt 

 give, causes me to make a few remarks on 

 the subject. 



It has been my experience that bees, while 

 gathering certain kinds of honey, are always 

 very cross, no matter what the weather or 

 other conditions may be; also that, while 

 gathering some honeys, they will always rob; 

 yet the same bees, when working on some 

 other plants, can not be induced to rob. 



For instance, bees are very cross when 

 gathering buckwheat honey. Coggshall. as 

 a rule, never takes off buckwheat honey 

 without gloves. No matter how good the 

 flow is, the moment you come near an api- 

 ary during a buckwheat flow, the bees are 

 ready for you. 



A case inopposition to the above is the bell- 

 flower of Cuba. Being a morning-glory it 

 closes very early in the day; but you can 

 take off honey all day long, and do it with- 

 out wearing a veil, if you are one of those who 

 make a practice of working without one; and 

 right here in Colorado, about two weeks ago, 

 during the alfalfa flow I saw Mr. Hickox, of 

 Berthoud, working beeschu-ing ([uiteaheavy 

 shower. He had a man holding a big uni- 



