10 



COLEOPTBEA OF INDIANA. 



one consists of two basal pieces and three outer parts. The first or 

 lower one of the former is called the cardo, and is 

 used to hinge the other parts of the maxillae to the 

 head. The second, the stipes, is jointed to the 

 cardo usually at a more or less acute angle, and 

 forms a place of support for the outer parts. These 

 consist of two lobes and one maxillary palpus. The 

 lobes vary much in form and sometimes one or the 

 other is so small as to be indistinct. The outer one. 

 Fig. 2. siaxiita of t i ga i ea j s fteu slender and divided into two 

 joints like a palpus. The inner lobe, known as the 

 lacima. is more or less jaw-like and its inner margin is armed with 

 flexible or stiff bristles, spines or teeth which are variable m form 

 and often used as brushes by pollen-eating beetles. The maxdlary 

 .alpus (plural palpi) arises from an upper segment of the stipes, 

 called the palpifer. The palpi are usually 4-jointed. rarely 3- 

 jointed (in the semis Aleoehara alone 5-jointed). The joints varj 

 greatly in size and form and are therefore much used m classifica- 

 tion ' The fourth one is most variable, sometimes being broad and 

 oval or subquadrate, more often triangular or hatchet-shaped. 

 When suddenly narrowed and more slender than the preceding, the 

 palpi are said 'to be subulate or awl-shaped. The development and 

 shape of the maxilla of beetles, as of other insects, depend very 

 largely upon the nature of the food, as those organs serve not only 

 to seize and hold the food in the mouth, but also as accessory jaws, 

 aiding the mandibles in rendering the food more suitable for swal- 

 lowing Their palpi are not only organs of touch, but in many 

 cases act as hands in prehending and carrying morsels of food to the 

 mouth. 



The floor of the mouth beneath and between the maxillae is 

 formed of two small pieces called the mentwn and the labium*. The 

 mentum is joined to the gula or throat, which is the region behind 

 or below the mouth, the suture between them being the mental su- 

 ture The mentum varies greatly in form and size and is often 

 notched or emanrinate in front, with a tooth at the middle of the 

 emargmation. When deeply notched the side-pieces are called lobes. 



The labium is usually in front of the mentum or in the notch 

 between the lobes; rarely it is almost entirely hidden. It is com- 

 posed of three parts, a central piece, the Jigula, and two side-pieces 

 called the paraglossa. The labium is often wholly horn-like in tex- 

 ture in which case the paraglossa are not distinct. In such case the 



