INSECTA. 



885 



TABLE OF THE PARTS AND APPENDAGES OF THE HEAD. 



Fixed parts of the head external surface, 

 (a) occiput, including the foramen occipitale and base of the skull, and forming part of 



b, epicranium vertex, Kirby epicrane, Straus. 



(b 1) ocelli stemmata. 



c, oculi corners, Straus. 



d, clypeus anterior > nasus, Kirby chaperon, Straus. 



</,*clypeus posterior . . . . $ clypeus, Fabricius 



w, gula, Kirby piece basilaire, Straus. 



e, labrum 

 f, mandibulae 



g, maxillae, 

 into . , 



Movcable parts of the head. 



PI, cardo, Kirby branche transversal e, Straus, insertio, Newman 



2, stipes, Kirby . . piece dorsale, Straus ; maxilla, Newman 



I 3, palpifer, Newman . .squame palpifer, Straus, bears 

 divided j 4, the maxillary palpus, h. 

 "S 5, lacinia, Macleay, Newman ; intermaxillaire, Straus, divided into 



6, galea, Fabricius ; lobus superior, Kirby. 



7, lobus inferior, Kirby. 



8, unguis, Kirby. 



i t labium 



I 



I 



t, ligula, Newman; labium, Macleay. 



k, the labial palpi. 



I, mentum, Macleay; labium, Newman ^ piece prebasi- 



m, submentum . . .. stipes, Macleay ; insertio, Newman S laire, Straus. 



12, lingua, Newman. . . . hypopharynx, Savigny. 



A, antennae . . . . 



rscapus. ~\ 

 . . . . < pedicella. > Kirby. 

 C. clavola. j 



Sub-segments of the head. 

 1st includes labrum and labium. 



2d includes clypeus anterior and mentum 

 3d includes clypeus posterior and submentum 

 4th, obsolete, orbits and bones of the antennae 



5th includes epicranium and gula 



The above table exhibits the whole of the 

 parts yet found in the cranium in the most 

 perfect order of Insects, the Coleoptera; but it 

 must be remembered that many of these parts 

 are less perfectly developed in the other Orders, 

 and in some of the species have not yet been 

 discovered. 



Commencing our examination of the head 

 at the posterior part of its upper surface, we 

 observe that the occiput (a, jig. 369 J is that 

 portion of its base which is articulated with 

 the anterior margins of the prothorax. It is 

 perforated by a large foramen, through which 

 the organs of the head are connected with 

 those of the body. It is very distinct in the 

 Hydrous and most Coleoptera, and in some, 

 the Staphylinida, Carabida, and Silphida, is 

 constricted, and extended backwards so as to 

 form a complete neck; but in others, as in the 

 Cwculionid&f it is short and hardly distin- 

 guishable from the epicranium (6), of which it 

 is the continuation and posterior boundary. 



Interior of the head. 



f os epipharyngeum, 



( os hypopharyngeum anterius. 



os hypopharyngeum posterius, z. 

 ( laminae orbitates, w ; and ossicula antenna- 

 ^ rum or toruli, r. 

 , sutura epicranii, p. 

 \ os transversum, x. 



/ laminae squamosse, s and v ; lames laterales, 

 J Straus. 

 (.tentorium, Burmeister, u; arcade, Straus. 



The epicranium is the whole of the posterior 

 and upper surface of the head, bounded pos- 

 teriorly by the occiput, laterally by the corneae 

 and sides of the gula, and anteriorly by a tri- 

 angular suture which extends from the anterior 

 margin of the corneae to the middle of the 

 head between the eyes, where its apex unites 

 with a longitudinal suture which extends along 

 the median line to the occiput. This trian- 

 gular suture is a marked character in the head 

 of many insects, both in the larva and perfect 

 state, and is of great importance in deter- 

 mining the number of the sub-segments. It is 

 very distinct in the larvae of Lepidoptera, and 

 is as marked in the Melolonthidte and the 

 Staphylinid(E as in the Hydrous. In some of 

 the beetles it is indistinctly marked on the 

 upper surface, but forms elevated ridges on the 

 interior surface. This is particularly the case 

 in the Hydrous. In the Dyticus it is more 

 distinctly marked by a lighter colour of the 

 skull, while in the common dung-beetles, Geo- 



