110 WATT 
mandible with a strong indentation, that of left slightly sinuate, scythe-shaped, 
Each mandible bears a membranous prostheca between scissorial and molar parts, 
that of right mandible rather larger than that of left, Prosthecae fill very deep 
indentations between scissorial and molar parts, that of the right mandible being 
larger. Molar surface of right mandible fairly regular, that of left irregular, with two 
prominent cusps at its distal edge, joined by a slightly lower transverse ridge. 
Proximal part of mola bearing a membranous, densely setose appendage. 
Maxillae (Fig.12), symmetrical. Cardo, stipes (which is composed of two 
sclerites showing no signs of fusion, as in most tenebrionids) and palpifer finely, 
sparsely and irregularly punctate, each puncture bearing a very fine, short seta. The 
position and presence of the large stout setae appear to be fairly constant. Terminal 
segment of palp securiform. 
Labium (Fig.13) with prementum somewhat retracted under mentum. 
Mentum bearing fine, rather sparse punctures, those of lateral depressions bear 
moderately long, stout setae, while those elsewhere bear very fine short setae. 
Basal and second segments of palpi each bear a ring of relatively long, stout setae 
near their apices, all segments bear smaller setae elsewhere. Apical margin of 
terminal segment bearing numerous small papilla-like sensilla. Ligula trilobed, 
densely setose on the areas shown in Fig. 11 (the lateral lobes are dorsal in position, 
and their setae arise on the dorsal surface of the ligula). Submentum not 
distinguishable, fused with postgenae. 
Ventral surface of head (Fig.5). There is disagreement concerning the terminology 
of ‘sclerites’ (topographical areas) of the head. Imms (1957) names the lateral and 
ventral regions of the head in Coleoptera (excepting the gula) the genae, and many 
coleopterists use the term in this sense. Snodgrass (1935, fig.67) refers to the 
ventral areas from the base of the maxillae backwards (excluding gula) as 
postgenae. This is also the nomenclature used by Koch (1955). In this revision the 
term postgena is used in the sense of Snodgrass and Koch to describe the 
ventrolateral surface behind the maxillae and lateral to the gula. The genae 
constitute the genal canthus, and the areas directly in front of, below and behind 
the eye (Fig.6). 
Head shallowly constricted behind eyes and just in front of gula (Fig.5). 
Pregular region of postgenae distinctly emarginate at base of cardo, edge of 
emargination forming a distinct, usually rounded, marginal ridge, outer angle of 
maxillary emargination obtusely raised or (in M. tibialis) dentate. Pregular region 
usually moderately deeply and closely punctured, with micropunctures between 
macropunctures. Gular region of postgenae usually more finely punctured, with 
punctures in irregular transverse grooves. All the macropunctures bear fine setae, 
usually visible at 25 x magnification. Gula triangular, surface generally impunctate 
and shining, frequently with irregular transverse or longitudinal grooves or 
wrinkles: 
Endoskeleton of head. Not studied in detail. 
Ventral surface of prothorax (Fig.4). Prosternum as in Fig.4, generally finely 
punctate and shining, sometimes granulate, often more or less laterally rugose. 
Intercoxal process with distinct submarginal grooves, posterior projection bulbous, 
more or less prominent. ‘Proepisternum’ as in Fig.4 (pr.ep.). actually represents 
