THE HEAD. 51 



The sides of the head, from the eyes downwards to the mouth, are 

 called CHEEKS (gencp, PI. III. f. 14, E), particularly when they consi- 

 siderably protrude, as in some of the Diptera (Myopa\ We again 

 distinguish in them the anterior portion, extending as far as the 

 articulation of the mandibles and maxillae., or the commencement of 

 the mouth, by the name of reins or LORA (lora, PI. III. f. 13, E), and 

 the posterior portion lying proximate to the eyes, as the TEMPLES 

 (tempora, PI. III. f. 13, F). 



The back of the head around the commencement of the neck is the 

 OCCIPUT (occiput, PL III. f. 12 14, G). In many instances, chiefly 

 among the Coleoptera and Ortlioptera, in which the longitudinally 

 formed head is deeply withdrawn within the thorax, this portion is not 

 at all visible, but it is prominently perceptible in the Diptera and 

 Hymenoptera, which carry their heads free. The aperture behind the 

 head, through which the internal organs are continued, is called the 

 OCCIPITAL FORAMEN (foramen occipitale). 



In many insects the commencement of the nock is likewise an inte- 

 gral portion of the head. The NECK (collum) is that part which unites 

 the head with the thorax. In the majority it is merely a membranous 

 tube, and it is among a few of \\ieColeoptera only (Staphylinus, Leptura} 

 that the back of the head is constructed into a short corneous cylinder, 

 to which the membrane of the neck is attached. Some entomologists 

 call this part the COLLAR (collare), a name which is applied by 

 others (for example, Klug, Kirby and Spence,) to the prothorax of the 

 Hymenoptera. 



THE MOUTH (Os). 

 68. 



From this consideration of the different parts of the head we pass on 

 to the investigation of the several organs attached to it. These are the 

 PARTS OP THE MOUTH, the ANTENNA, and the EYES. 



The ORAL ORGANS, or parts of the mouth (partes oris, instrumenta 

 cibaria, trophi) lie at the anterior, or inferior part of the head, and 

 surround the MOUTH (os). When attached to a long corneous and 

 generally cylindrical prolongation of the head, this part is called the 

 snout or ROSTRUM (rostrum), which, however, must be well distin- 

 guished from the proboscidal prolongation of the oral organs them- 

 selves ; the rostrum being merely a continuation of the corneous cover- 

 ing of the head, and not a distinct organ. 



E 2 



