2\] THE HEAD-CAPSULE OF COLEOPTERA—STICKNEY 21 



(Fig. 143) and Sphenophorus (Fig. 145) it is very extensive, including 

 practically all of the snout of the dorsal and lateral surfaces. The area 

 on the lateral surfaces of the head, cephalad of the compound eyes, be- 

 tween the latter and the epicranial suture, is the gena, a part of the vertex. 

 The limits of the gena are not definite. The prominent ridge in many 

 genera, dorso-mesad of each gena and antacoria, is the so called frontal 

 ridge, that extends in the general direction from the epicranial arms to the 

 mesal margin of the compound eyes. The frontal ridge is prominent in 

 Harpalus (Fig. 5), Necrophorus (Fig. 18), Trichodes (Fig. 41), Neopyro- 

 chroa (Fig. 54), Dermestes (Fig. 74), and many others. 



In generalized insects the occipital suture is confined to the ventral or 

 caudal aspect, beginning near the lateral margin of the postcoila and 

 extending around the caudal or dorsal margin of the occipital foramen. 

 In the Coleoptera this suture arises laterad of the postcoila, extends 

 cephalad for a considerable distance, then cutves abruptly laterad, ex- 

 tending onto the dorsal aspect of the head, where it joins the suture of the 

 other side of the meson. The genus Cicindela (Figs. 3, 151, and 298) 

 possesses the most generalized condition of this suture found in the Coleop- 

 tera. The cephalic end of the suture is modified into a ridge. This 

 ridge is considered a later development, and is not shown in the hypothetical 

 tvpe. It unquestionably represents a part of the occipital suture, and can 

 be identified in practically all the Coleoptera, as in such widely separated 

 groups as Molamba (Fig. 168), Nacerda (Fig. 195) and Byturus (Fig. 237). 

 The occipital suture separates the vertex from the occiput and the post- 

 gena. Only the Caraboidea seem to possess with certainty an unmodified 

 occipital suture. In Cicindela (Fig. 3) it is complete and nearly so in 

 Tetracha (Figs. 2, 150, and 297), but very faint in great part. In Calo- 

 soma (Fig. 152) the unmodified suture begins farther caudad and is more 

 distinct. In Omophron (Fig. 302), two short, characteristically curved, 

 lateral ridges no doubt represent remnants of the occipital suture. The 

 ridge across the lateral aspect in Peltodytes (Fig. 303) may also represent 

 this suture. In Cybister (Fig. 157) it is probably represented by the 

 crescent-shaped suture on the ventral aspect. Ridges and furrows ap- 

 pearing in the same general location in other species, such as Aleochara 

 (Fig. 321), Throscus (Fig. 356), Cyphon (Fig. 365), and Aphodius (Fig. 

 405), may possibly be homologized as occipital sutures. In most cases 

 these ridges seem to be merely to mark the limits to which the head is 

 telescoped in the prothorax. 



In those species possessing an occipital suture the occiput is recognized 

 as a distinct area. It includes the region between the occipital foramen 

 and the occipital suture as far as the postgena, appearing as a sort of broad 

 band across the dorsal aspect, divided by the epicranial stem and in- 

 distinguishably fused on the lateral aspect with the postgenae. Examples 



