THE MOUTH-PARTS OF SOME BEETLE LARViE. 
385 
tlie dorsal surface, forming two lateral lobes ( l.l .) which over- 
hang the articulation of the lateral and anterior sclerites. 
Dorsally towards the middle of the body of the tongue two 
small triangular sclerites occur. They seem to be merely 
little thickened elevations on the general basal sclerite. 
On the dorsal surface of the hypopharynx occur two 
prominent lobed, toothed sclerites ( mxl .), which from their 
position and similarity to the maxillulae of Helodes are, we 
have no doubt, true maxillulas, which have become, as usual, 
somewhat fused with the tongue. 
They are jointed on to the lateral sclerites, but are not 
movable owing to this partial fusion with the hypopharynx. 
The lobes are convex dorsally. The delicate cuticularised 
inner edge is closely apposed to the tongue, and is very finely 
striated. The dorsal edge is toothed, bearing usually about 
twelve teeth, most of which are bifid. Along the margin 
behind the teeth are a number of delicate spines. 
As mentioned above, Rivers (*91, p. 94, pi. ii, fig. 4) has 
described and roughly figured a somewhat similar arrange- 
ment of teeth on the hypopharynx of the larva of Dascillus 
Davidsonii. The appendicular nature of the lobes that 
bear the lateral series of teeth would hardly be suspected 
except on comparison with the corresponding structures in the 
Helodes larva. The strong development of these maxillulae, 
in correlation with the functional activity of their teeth 
working vertically against the teeth of the epipharynx, is a 
most interesting feature. 
Maxillas. (PI. 36, figs. 16, 17.) 
The maxilla conforms very remarkably to the type found 
in adult insects, and thus indicates the primitive character of 
this larva. 
It consists of a horizontal basal segment, the cardo (car.), 
succeeded by a vertical segment, the stipes (stp.), which 
bears a segmented palp (pip.) externally and two lobes, galea 
and lacinia, internally. 
