29] THE HEAD-CAPSULE OF COLEOPTERA—STICKXEY 29 



families, as Nosodendron (Fig. 224), Anoplitis (Fig. 236) and Tetraopes 

 (Fig. 272), almost the same degree of primitiveness is shown. The large 

 superfamily Mordelloldea show the metatentorinae to have migrated to 

 about half the distance between the occipital foramen and the submentum. 

 This condition is fairly consistent throughout the group. In the Bostri- 

 choidea, the Scarabaeoidea, and the Cerambycoidea, the metatentorinae 

 show considerable variation in position. This is shown by a comparison of 

 their position in Bostrichus (Fig. 256) and Sphindus (Fig. 258). In the 

 famihes to which Tetracha (Fig. 150), Calosoma (Fig. 152), Cybister 

 (Fig. 157), Dineutes (Fig. 158), Necrophorus (Fig. 166), and Glycobius 

 (Fig. 271) belong, the metatentorinae have advanced very far cephalad, 

 near to the submentum. In Photinus (Fig. 183) and Chauliognathus 

 (Fig. 185) they are located on or quite near the paracoila. 



There is a narrow plate surrounding the lateral and caudal margins 

 of the occipital foramen in some generalized insects, between which and the 

 postgenae the metatentorinae are invaginated. This plate has disappeared 

 in the Coleoptera. 



The structure connecting the head-capsule with the prothorax is 

 called the cervix. It is normally com.posed of membrane, and a number 

 of cervical sclerites. The size of the cervix depends upon the size of the 

 occipital foramen, and the degree of mobility of the head. In the Lampy- 

 roidea and some other forms the cervix is very large. The cervix in 

 Rhysodes is composed of tough fibrous membrane, quite different in 

 structure from the normal cervix. In nearlv all of the Rhynchophora the 

 cervix is heavily supported by strong tendons attached at its cephalic 

 end. These tendons take care of the added strain on the cervix due to 

 the elongation of the snout. There are more or less small cervical tendons 

 appearing occasionally throughout the whole series of famihes studied. 

 In INIolamba (Fig. 21) the cervix is invaginated within the prothorax, 

 doubling upon itself. The cervix in Bostrichus (Figs. 256 and 401) 

 doubles back upon the head-capsule, which is produced into a round 

 projection. 



The most prominent and persistent cervical sclerites are the pleural 

 cervical sclerites, the cervepisternum and the cervepimeron. The former 

 is usually the larger of the two, and articulates at its cephalic end either 

 against an odontoidea or simply against the undifferentiated area sur- 

 rounded by the occipital foramen. The latter usually extends in a different 

 direction from the former, and articulates at its cephalic end with the cerve- 

 pisternum and at its caudal end with the prothorax. In Cantharis (Fig. 

 187),Macratria (Fig.348),Psephenus (Fig. 358) and others, there is a single 

 large sclerite present. In the Adephaga, in Leptinus (Fig. 312), Hypor- 

 phagus (Fig. 397), Pseudocistela (Fig. 392), and many others, there is a 

 single small subcircular sclerite present. Both of these types probably 



