Mouth Organs of Intccts. 45 



or more teeth. A rudimentary tooth (Fig. 24, a, 6) is visible 

 on the jaws of drone and queen bees. • 



Ueheath the jaws or mandibles, and inserted a little farther 

 back, are the second jaws, or maxilla? (Fig. 7, mx), less dense 

 and firm than the mandibles, but far more complex. They 

 arise by a small joint, the cardo ; next this is a larger joint, 

 the stipes ; from this extends on the inside the broad lacinia 

 (Fig. 22, c) or blade, usually fringed with hairs on its inner 

 edge, towards the mouth ; while on the outside of the stipe, 

 are inserted the — from one to several jointed — maxillary palpi. 

 In bees these are very small and consist of two joints, and in 

 some insects are wholly wanting. Sometimes, as in some of 

 the beetles, there is a third member running from the stipes 

 between the palpus and lacinia called the galea. The max- 

 illa? also move sidewise, and probably aid in holding and turn- 

 ing the food while it is crushed by the harder jaws, though in 

 some cases they, too, aid in triturating the food. 



These mouth, parts are very variable in form in different in- 

 sects. In butterflies and moths, two wing flies and bugs, they 

 are transformed into a tube, which in the last two groups forms 

 a hard, strong beak or piercer, well exemplified in the mosquito 

 and bed-bug. In all the other insects we find them much as in 

 the bees, with the separate parts varying greatly in form, to 

 agree with the habits and character of their possessors. No 

 wonder De Geer and Fabricius detected these varying forms 

 as strongly indicative of the nature of the insect, and no won- 

 der that by their use they were so successful in forming a 

 natural classification. 



If, as is more than probable, the "Doctrine of Selection" 

 is well founded, then a change in habit is the precursor of a 

 change in structure. But what organs are so intimately re- 

 lated to the habits of animals, as the mouth and other organs 

 that have to do with digestion ? 



Every apiarist will receive great benefit by dissecting these 

 parts and studying their form and relations for himself. By 

 getting his children interested in the same, he will have con- 

 ferred upon them one of the rarest of blessings. 



To dissect these parts, first remove the head and carefully 

 pin it to a cork, passing the pin through, well back between 

 the eyes. Now separate the parts by two needle points, made 

 by inserting a needle for half its length into a wooden pen-holder, 



