2i] THE HEAD-CAPSi'LE OF COLEOPTERA—STICKXEV 2? 



supratentoria are usually attached to the inner membrane of the body-wall, 

 but unless an actual mark of their presence is indicated on the external 

 surface the supratentorinae are not considered as present. In generalized 

 insects the latter are generally present. Their presence in the Coleoptera 

 should indicate a primitive state. 



In all the Coleoptera examined, no indication of any ocelli has been 

 observed. 



In generalized insects there is a ring-like sclerite surrounding the 

 periphery of each antacoria. In Coleoptera this sclerite is present, but 

 it is distinguished from the head-capsule by a ridge only. On most heads 

 it is considerably reduced in size, about all that can be seen of it externally 

 being its projection, the antacoila, upon which the scape of the antenna 

 articulates. On the other hand, in Sandalus (Fig. 553i), Derobrachus (Fig. 

 120), Tetraopes (Fig. 124), Leptinotarsa (Fig. 130), and .\nopHtis (Fig. 

 133), the antennaria is quite prominent. The most generalized position 

 of the antennaria is considered to be on the gena cephalad of the eye, 

 notwithstanding that in generalized insects the antennariae are quite fre- 

 quently found distinctly between the eyes. Embryology, however, 

 shows that the antennae are postoral in origin. Furthermore, in coleop- 

 terous larvae each antennaria is located cephalad of the ocellarae. Such 

 a position in coleopterous adults should denote the more generalized condi- 

 tion. The antennaria is very unstable in position. There is hardly a 

 superfamily in which it does not appear in both the generalized position 

 and elsewhere. In the Scarabaeoidea and Cerambycoidea, though the 

 position of the antennaria varies within certain limits, yet it shows a char- 

 acteristic location. In the former it is either on the lateral or ventral 

 aspects, while in the latter it occurs only on the dorsal aspect. In no other 

 large groups does the antennaria appear so constant in position. In 

 Calopteron (Fig. 36) and Phengodes (Fig. 38) it is exceptionally large; in 

 Dineutes (Fig. 305) and Alobates (Fig. 392) it is exceptionally small. 



The membrane attaching the antenna to the head-capsule is the 

 antacoria. In removing the antennae the antacoria is torn, and as it plays 

 no significant part in this study no attempt was made to represent it in 

 every case. The antacoria varies in size depending upon the size and 

 shape of the scape. It is indicated in a number of figures by the stippled 

 area: Omophron (Fig. 7), Necrophorus (Fig. 313), Calopteron (Fig. 36), 

 Phengodes (Fig. 38), and Chauliognathus (Fig. 332). 



The depression in the vertex, usually in the gena, within which the 

 antennaria and antacoria are situated is the antacava. It is always pres- 

 ent, so far as is known, and is developed into a deep socket in Dineutes 

 (Fig. 305), Connophron (Fig. 315), Scolytus (Fig. 441), and Dendroctonus 

 (Fig. 442). 



The points of invagination of the pretentoria on the head-capsule are 

 the pretentorinae. They are always located along the epicranial suture 



