SPRUCE BARK-BEETLES. 
825 
different species, and indeed it is probable that from variations in age 
and size, too many species of these bark-borers have been described. 
Leconte states that the genus Xyleborus has "the body stout, cylin- 
drical ; declivity of elytra oblique, scarcely flattened ; funicle of an- 
tennae with four distinct joints ; tibiae finely serrate on the discal half 
cl 
Fig. 277. — c. mine, with eggs, of Xyleborus ccelatus. 
Gissler del. 
278.— Xyleborus ccelatu*. 
J. B. Smith and Miss 
Sullivan del. 
of their length and rounded at tip." X. ccelatus ranges from Canada to 
Texas and California. In this species " the declivities of the elytra at 
the end of the body are with two prominent tubercles, and some smaller 
marginal ones ; elytra strongly punctured in rows : interspaces with 
rows of distant punctures." (Identified by Dr. Horn.) See also p. 709. 
3. The least spruce bark-borer 
Crypturgus atomus Le Conte. 
(Larva, Plate xxiv; figs. 4, 5, 5a, 55; pupa 5c.) 
Order Coleoptera; family Scolytid^e. 
This minute bark-borer, though often occurring in white-pine bark,, 
must not be confounded with Pityophthorus puberulus of the white pine 
(p. 715), as its burrow is very different. The present species is l-j- mm 
long, and f mm in diameter. The mine consists of a short sinuous pri- 
mary gallery about one-half inch long, which gives off at intervals about 
ten short secondary galleries from each side, but they are not made in 
the same plane, next to the sap-wood, as in P. puberulus, but penetrate 
only the bark itself in all directions, so that no regular pattern is formed. 
The beetle is extremely numerous, a great many mines being densely 
situated within a square inch of surface. They were observed in great 
profusion in the larva, pupa, and beetle states at Brunswick, Me., dur- 
ing August; in standing dead trees as well as spruce stumps; also in 
white-pine stumps. Many of our observations on this and the fore- 
going species, as well as the Rhagiuin, were made by the side of Maquoit 
