THE CLOVER ROOT BORER 7 
ima Valley, western Washington from Oregon to the Canadian boun- 
dary); and in western Oregon, at least as far south as Medford. | 
Figure 1 presents the known distribution in the United States. 
The wide distribution of this species over regions of the world 
where red clover is a common crop and its early appearance in most 
new clover regions would indicate that the species is readily trans- 
ported by commercial intercourse. Root borers may be transported 
in hay shipments, because the beetles are sometimes found mining in 
the stems of clover, and, in cases of severe infestation, the clover 
tops and even portions of the root crown may be pulled out by 
the mower and become part of the hay. Adult root borers may 
also be transported in soil taken from the vicinity of clover plants, 
and in other ways during the period of flight, when they are often 
found in unexpected places. 
DESCRIPTION 
EGG 
The egg (fig. 2) is short-oval in shape, with one side somewhat less 
rounded than the other, pearly white in color, smooth and glistening. 
Eggs in which development has begun are transpar- 
ent at one end, because of retraction of the egg con- 
tents; whereas the fresh eggs are altogether opaque. 
The egg measures 0.67 mm. long by 0.43 mm. wide at 
the widest part. Eggs are 
found in niches, which are 
plugged with wads of frass, 
in the walls of the egg 
galleries. 
LARVA 
Fig. 2.—Egg of clover 
The mature lanya, (Ag. 3). :- foe borer, 28 
is of the usual scolytid type, 
«4 short subcylindrical, wrinkled, and legless. 
~~ The thoracic region is distinctly larger than 
the abdominal region, which tapers gradu- 
ally posteriorly. The body set are short, 
fine and sparse, very obscure. The color 
is creamy white, with straw-yellow to light- 
brown head capsule and red-brown, trian- 
gular, dark-tipped mandibles, which have 
two broadly blunt teeth at the apices. The 
immature and still feeding larve appear 
dirty white or gray, because of the contents 
je of the intestinal tract. The sete of the 
Fic. 3.—Larva of clover mot borer, Head are light colored, fine, somewhat longer 
lateral view, x16 diameters than the body sete. The head capsule 
; (fig. 4) has the epicranial suture ° strongly 
impressed; front with a convexity anterior to the middle, with oblique 
ridges extending above to the sutures of the front on either side and 
below to the angles of the epistoma, forming concavities between the 
ridges. Front with posterior apex subacute. Labrum with raised 
_§ The anatomical nomenclature here used is for the most part that of A. D. Hopkins, in his treatise on 
the Genus Dendroctonus (20). 
