160 ARTHROPODA. 



4. Watch the entrance of a bee-hive and see if those going 

 in are ever challenged. Perhaps you may see the method of 

 defense. If so, you will notice that the stranger simply tries 

 to get away. You may also see how dead bees and foreign ma- 

 terials are removed. 



5. It is desirable to see something of the activities in the hive. 

 This can be most satisfactorily done with an observatory hive, 

 by means of which comb-building, honey-storing, egg-laying, 

 brood-rearing, etc., can be very satisfactorily studied. 



Directions for the study of the mouth parts and the sting are 

 all that seem necessary, but the wings should be examined 

 microscopically to see how those of a side are joined together, 

 and a hind-leg should be examined to see how the hairs on the 

 tibia form a pollen basket. 



Mouth Parts. — 1. With a lens notice that there is a pair of 

 hard jaws, the mandibles, situated on the sides of the head at 

 the base of the tongue. These mandibles are directly homolo- 

 gous with the mandibles of the grasshopper. Between the bases 

 of the mandibles is a lahrum, and extending from beneath the 

 end of the labrum is a small epipharynx. 



2. With scissors remove the tongue, which is normally carried 

 against the lower surface of the thorax, and transfer it to a 

 watch-glass. It ma}^ now be dehydrated, j^assed into oil of 

 cloves, placed in position on a slide, and mounted in balsam, 

 when it can be studied best, or it may be immediately spread 

 under a cover or between slides in glycerin. 



3. The central portion is the hairy, segmented labium (the 

 hypopharynx of some authors), bearing at its end a little pad 

 called the spoon. The labium is folded lengthwise so as to form 

 a pair of fine ducts which run from tip to base. The arrange- 

 ment is such that the bee may, through blood-pressure, unfold 

 the labium. This probably is an adaptation for cleaning it. 

 Attached to a median rod, the mentum, which forms the base 

 of the labium, is a pair of flattened appendages, the labial palps, 

 that are hinged so that they may be drawn together to inclose 

 the labium and thus form a rather large tube, which is made 



