94 
is not a pest as yet, tho Mr. J. A. West, assistant to the State Ento- 
mologist, found alsike injured by it at Monticello in 1907. 
•^ 
'Mllj^ 
Fig. 18. 
Fig. 19. 
Fig. 20. 
Clover Root-borer, Hylastinus obscurus: Fig. 18, beetle; Fig. 19, larva; Fig. 20, pupa. 
Greatly enlarged. (Webster, Circ. 67, Bur. Ent., U. S. Dept. of Agriculture.) 
Stages. — The beetle (Fig. 18) is small — at most only 2.5 mm. in 
length — dark brown or blackish, cylindrical, hard-bodied and hairy. 
The elytra, or wing-covers, often have a reddish tinge, and are coarsely 
punctate ; and the head and pronotum are more finely punctate, the lat- 
ter bearing sparse long hairs. The tibice have large teeth near the outer 
end. 
The egg is minute, tho visible to the naked eye, white, and elliptical, 
with a smooth, shining surface. 
The larva (Fig. 19) is stout, white, with yellow head and brown 
mouth parts, footless, and 3 mm. long when full grown. 
The pupa (Fig. 20) is white, with a pair of spinelike projections 
at the extremity of the abdomen, and another pair on the top of the 
head. The pronotum shows a feeble median ridge and bears a few 
scattering bristles. 
Life History and Habits. — There is but one generation a year. In 
Ohio, where Webster- worked out the life history, the insect winters in 
clover roots as a beetle and also, tho less commonly, as a larva, the 
latter pupating in spring. The beetles leave the roots during May and 
fly about. The eggs are laid mostly from May 15 to June 20 in cavi- 
ties eaten out by the females in the crown of the plant or down on the 
sides of the roots. In each cavity the female lays several eggs. Mr. 
G. C. Davis found females laying eggs inside the root, in the burrows, 
the eggs being packed into the dead wall of the burrow and covered, 
with refuse. The larvae, the first of which hatch late in May, feed for 
a time where they hatched, then tunnel along the roots, making one or 
more longitudinal galleries with occasional side branches, and filling 
the burrows with excrement. The pupa is found at the end of a bur- 
row. Most of the larvae pupate before the first of August and most of 
the pupae transform to beetles before the first of October. The beetles 
