14 
swollen and about one twelfth of an inch thick. The remainder of 
the body is more slender, slightly tapering to the smoothly rounded 
posterior end. The head is pale brown, and the mandibles and the 
narrow front border of the clypeus are dark, in decided contrast 
with the labrum, which is whitish. The first segment hack of the 
head is faintly brownish, shining except for a dull pubescent ridge 
along the hind border. The remaining segments, except those near 
the posterior end, which are smoother, hear two such dull ridges. 
On the abdominal segments these ridges extend to the spiracles on 
each side, and behind them is an additional shorter ridge of similar 
appearance. The folds beneath the head are also dull pubescent. 
Fig. 4. Elm twig with bark cut away to show burrow of 
Magdalis armicollis. (Enlarged 3 diameters.) 
The beetles, which develop beneath the bark and escape from it 
by eating small round holes to the surface, are from an eighth to 
a quarter of an inch in length, the sexes differing to such an ex¬ 
tent that they were originally described as separate species. The 
male is, in fact, decidedly smaller than the female, darker beneath, 
and with a much more marked contrast in color between the wing 
covers and the thorax. The wing covers are yellowish, or pale 
reddish brown, and are each marked with nine deep longitudinal, 
coarsely punctured, grooves. The thorax and the head are decid¬ 
edly darker, especially in the male, in which they are frequently 
black. The thorax is narrower than the wing covers, broadly 
rounded laterally and very densely punctured above and on the 
sides, with a more or less evident smooth median raised line. The 
body beneath is pale reddish brown in the female, and black in the 
male. The projecting, slightly curved snout is about as long as 
the thorax, and bears the antennae near its tip. 
The larvae pupate in spring within the tree, and the beetles 
emerge in about three weeks, pairing and laying their eggs in May 
and June. 
