1878.] 667 (Hubbard. 
divided anteriorly by a deep notch into two portions, the apical, smaller 
and narrower than the basal, blade-shaped, tipped with a long slender spine, 
and bearing four long and stout teeth projecting at right angles to the lobe, 
like the blades of a half-opened penknife ; the basal portion with two rows 
of teeth on the border, and a slender tooth and bristle at the apex. 
Labium consisting firstly, of an elongated, triangular mentum, with the 
apex thickened in aconical protuberance, bearing a pair of bristles near the 
middle, and another pair upon the thickened tip ; secondly, of a transverse 
palpiger, bearing small fleshy palpi of two subequal joints, and its anterior 
border prolonged between them in a conical projection; thirdly, of an 
elongated, convex, corneous ligula, enlarged anteriorly, with straight 
borders and a pair of bristles near the tip. Behind and above the mentum 
and plainly seen through the transparent tissues, is a broadly triangular, 
horny piece, the base of which extends between the hinges of the mandi- 
bles, and the apex reaches as far as the middle of the ligula; upon the 
upper surface oblique grooves on each side correspond with the ridges 
upon the basal lobes of the mandibles, into which they lock when the man- 
dibles are closed.* 
Thoracic segments slightly thicker than the abdomen, the first longer, 
the two following subequal in length. 
Abdomen cylindrical or slightly depressed, of nine segments, the first 
eight subequal, transverse, each with a few long bristles, the ninth conical, 
scatteringly covered with long bristles, terminating abruptly in two minute 
toothed appendages, one proceeding from the dorsal surface, and arching 
downwards, the other from the ventral surface, curving upwards, and re- 
sembling two hands with partly extended fingers, having the palms 
turned towards each other. The upper and longer appendage appears to 
be tubular for one-third of its length from the base, the remainder is con- 
cave beneath, and terminates in two terminal and six lateral teeth, directed 
downwards, their bases forming longitudinal ridges on the concave under 
surface. The lower appendage is shorter, more strongly curved, and in the 
opposite direction, concave above, expanded into a palm at the end, with 
eight teeth as in the preceding; the concave upper surface is distinctly 
denticulate. 
The larva lives in damp situations, in the soft, crumbling wood of old 
oak logs, which have become entirely disintegrated and colored dark red, 
probably by a microscopic fungus. A number of larvee, pupze, and imagos 
were found together in a small portion of such a log on August 17th, 1874, 
at Detroit, Michigan. 
As Dr. LeConte has placed this insect in the family Lymexylide, it will 
be interesting to compare its larva with that of Hylecetus lugubris Say, 
specimens of which are before me. The larve of Hylecwtus were taken 
from cylindrical burrows in the solid wood of the American linden, It 
* This piece and the mandibles, the forms and relative positions of which are 
shown in fig. 9 of the plate, though very conspicuous in dissections under the 
microscope. are omitted in fig. 5 in order to avoid obscuring overlying parts. 
