252 INSECTS INJURIOUS TO FOREST AND SHADE TREES. 
connection descriptions of the different stages of this species, which 
has only yet been found in Illinois by Dr. Shimer, to whom I am 
indebted for specimens, would seem necessary, inasmuch as they throw 
light on the structure of the apple Leiopus. According to Dr. Shimer 
it bores into the limbs of the prickly ash. 
The larva (Fig. 99, a, larva; b, upper side ; ce, under side of the head) is 
N xr ‘ 4 
IRCA He; 
\ $ex- : YS ad 
ry 
pee 
Fic. 87.—Liopus_xan- Fic. 98.—Liopus facetus.— Fic. 99.—The prickly ash borer.—From Packard. 
thoxyli.—From Pack- From Packard, 
ard, 
very much like that of the preceding species. The head is a little 
more than half as wide as the prothoracic ring. The basal (occipito- 
epicranial) region is transversely oblong, the basal piece (occiput) being 
very short, and transversely almost linear, and separated by a well- 
marked suture from the middle portion (epicranium) of the head, the 
latter being nearly four times as broad_as long, with the front edge 
straight; it is white, with the front edge pitchy black. The clypeus is 
smooth, trapezoidal in form, and three times as wide as long. The upper 
lip (labrum) is thin, hairy, transversely elliptical, a little less than one- 
half as long as broad. The basal chin piece (submentum) is a large 
transversely oblong area, with the front edge piceous, and very slightly 
hollowed, while the posterior edge is very deeply hollowed out. The 
chin (mentum) is nearly square, widening at the base, which is continu- 
ous with the base of the maxill, the whole posterior edge being well 
rounded. The labial palpi are three-jointed, the basal joints of each 
palpus being large, and no longer than broad, and touching each other ; 
the second joint is much slenderer, and about half as thick as the basal 
joint; the third joint is not quite so long, and is searcely half as thick 
as the second; its tip is acute and reaches out as far as the end of the 
second joint of the maxillary palpi. The maxillary palpi are four- 
jointed, very broad at the base; the first joint is scarcely half as long 
as broad; the third is a little longer than the second, while the fourth 
is much slenderer than the others, and about the length of the second 
joint. The mandibles are large and powerful, when closed not reaching | 
as far as the end of the maxillary palpi; the ends are truncated, gouge- 
like. On the prothorax is a large, obscurely marked, squarish, very 
slightly horny (chitinous) area, scattered over with hairs, especially on 
the anterior edge. On the upper side of each segment of the body is a 
