584 Mr. D. Sharp and Mr. F. Muir on the Comparative 
Lyctus canaliculatus (Pl. LXIII figs. 1382, 132a). 
This appears to be a trilobe form, with a long, thin median lobe 
pointed at apex, and long lateral lobes, flattened laterally, the basal 
part of the median lobe is curved upwards and is articulated to the 
base of the lateral lobe. The basal-piece consists of a thin chitinous 
plate encircling the base of the lateral lobes, very narrow dorsally 
and wider ventrally. Internal sac undifferentiated. 
Lyctus rugicollis, . 
In this the aedeagus is much shorter as regards the lateral and 
median lobes, but the basal-piece is longer and more pointed. 
Tristaria growvellei is quite of the same type as Lyctus. 
Obs.—The Lyctidae forms are of great importance, as 
they may not improbably show an alliance with the 
Colydiidae group. There may even be an approximation 
to the Caraboidea. An examination of a larger series of 
Bostrichidae is required before coming to a conclusion as 
to these forms. At present Lyctus appears very different 
from Apate. 
Family PTINIDAE. 
Forms examined: Ptinus fur L., England. Ptilinus 
pectinicornis L. and Ernobius mollis L., England. 
Figs. 133, 184 and 1384a Pl. LXIV. 
Ptinus fur (Pl. LXIV fig. 133). 
Median lobe long, thin and curved at the base with the point 
of articulation on the dorsal aspect ; median orifice near tip on ven- 
tral face; median foramen at base. Lateral lobes long, narrow and 
asymmetrical, the right one being broadened out at tip, the left 
one more acute, basal-piece forming a small sclerite at the base of 
the lateral lobes, on the ventral side, its distal margin being deeply 
emarginate. Internal sac undifferentiated. 
This type approximates to Zyctus. Note the peculiar 
connection of the bases of the lateral and median lobes. 
Ernobius mollis (Pl. LXIV figs. 184 and 134q). 
Median lobe asymmetrical, curved, tubular, flattened at apex and 
expanded and strongly curved at base dorsally, where it articulates 
with the bases of the lateral lobes. Lateral lobes asymmetrical, the 
left one is twisted and the point acute, with a narrow base running 
along the edge of the basal-piece ; the right one has a rounded apex 
with a point below the apex, on the inner side, and the base is broad. 
