INTRODUCTION, 



2. (Jlavate : in this group the outer joints form a more or less 

 distinct club ; if it is abrupt the antennae are said to be capitate. 



3. Serrate : in these the joints are, in the typical form, triangular, 

 like the teeth of a saw, but as a matter of fact the group is 

 extremely variable. In many cases the last three joints only are 

 irregularly serrate and are considerably enlarged, forming a more 

 or less strong club, and therefore perhaps belonging rather to the 

 second group ; in others the joints are largely extended laterally 

 and the antennae are then called pectinate, and if extended on both 

 sides bipectinate (in certain Australian moths we even find tri- 

 pectinate antennae) ; in cases of further extension they are styled 

 jlabellate, or (when feathery) plumose. 



4. Lamellate : this is really a form of the clavate antenna, in 

 which the clava or club takes the shape of plates which oppose flat 

 surfaces to one another. The apposition may be loose (as in the 

 Melolonthid;e) or strong (as in the Geotritpidje) ; in the latter 

 case the antennae appear to be capitate at first sight rather than 

 lamellate. The small club of Lucanus is termed fissate. 



The above types are all that need be particularly noticed. 

 Certain others occur but they are really modifications of one or the 

 other of the four above-mentioned ; iu fact we may perhaps say 

 that all the forms are gradual modifications of the filiform type. 

 When the first joint is much prolonged the antennae are called 

 geniculate. This is usual in the B/hynchophorous series, in which 

 the first joint is styled the scape and the joints between the scape 

 and the club are called the funiculus. We find, however, 

 geniculate forms in other families also. 



The functions of the antennae are mainly sensorial. Graber states 

 that he has observed Longicorns using them as a sort of balancing- 

 pole when walking along a twig or small branch, but this adjust- 

 ment of balance would apply to all parts of the body in all orders, 

 and could not be described as a function of the antennae. 



The liead as a whole is firmly supported by the broad prothorax, 

 into which it is more or less sunk, or it is attached to a more or less 

 distinct neck. At the hinder part of the head there is the opening 

 (occipital foramen) into the trunk ; through the occipital foramen 

 the organs of the head are connected with those of the trunk. 

 This is very distinct in Hydrous and indeed in most Coleoptera. 

 The cheek (gena) is at the side of the head and to its inner wall 

 is attached the mandibular muscle. The walls of the head are 

 supported or braced within by the tentorium, which consists of a 

 central plate from which diverge two pairs of arms extending to 

 the skull : it braces the skull, affords muscular attachments and 

 holds in place the cephalic ganglia and the oesophagus (Folsom) : in 

 Coleoptera {Hydrous, etc.), it protects the nervous cord which 

 passes under it. 



The tlioracc is made up of three parts, the prothorax, mesothorax, 

 and metathorax ; these are often spoken of, for convenience' sake, 

 as the pronotum, mesonotum, and metanotum, but these terms should 

 properly be applied to the upper parts only, the lower portions 



