146 
TflE ORDER OP COLEOPTERA. 
I n s- 71 -J This family is coextensive 
with the tribe of short-horned 
borers which we have just de- 
scribed. They are usually re- 
garded as closely allied to the 
Curculionid® ; but, as we have 
stated above, they differ great- 
ly from the latter in their food- 
habits, and also in the details 
of their organization. In ad- 
dition to the characters given 
above, we may add that they 
differ from the great majority 
of the tetramerous beetles, in- 
cluding the Curculionidae, in 
having simple tarsi, not spongy 
beneath, and with the last joint 
but one not at all, or but very 
slightly, bilobed. In Dr. Le- 
Conte’s sketch of this family in 
the 2d Vol. of Trans, of Am. 
Scolytus 4-8PIN08US, Say: S. CARY.®, Riley 1 shows the .,.><1 
burrows of the larvffi between the bark and the wood, OOC16tYj 0110 HUU(lr6Q alltl 
growing wider as they diverge from the line where the "M" A nrAPiin- 
egg* are deposited ; 2, another view of the same, showing bliltJO A. opcUco cue tsuu 
the hole made by the exit of the beetle; 3, beetle, both mOT ,„ i /licfri hntn/1 in Aio h 
magnified and natural size; 4, larva, the same; 5, pupa merd-ieilj (llSinUUXCu 111 
maguiflert— after Kiiey. teen genera or sub-genera. 
But all the more common species may be included in the six following 
genera : 
A. Head free ; 1st joint of the tarsi as long as the others united PLATYPUS. 
A A. Head deeply inserted in thorax ; first joint of tarsi much shorter than the others united. 
B. Abdomen of the usual form. 
C. Head not globular, visible from above; 3d joint of the tarsi slightly bilobed. 
D. Knob of the antennas sub-globular. 
E. Six joints in the an ten me before the knob Hylurgus. 
E E. Seven joints in the antenna; before the knob Hylabteb. 
D D. Knob of the antenn® ds long as the preceding joints united Hylksinus. 
C C. Head globular, invisible from above; 3d joint of tarsi not bilobed Tomicus 
B B. Venter turned up behind Scolytus. 
The Platypus compositus, Say, may be taken as a type of this genus in 
this country. It is one-fifth of an inch long, of a reddish-brown color, 
and each elytron has a three-toothed elongation at its extremity. Dr. 
Chapuis, in his monograph of this genus, describes nine N. American 
species, none of which are very common. 
Hylurgus, Latreille, contains a number of well known species, the 
largest and most common of which is the H. terebrans, Oliv., of a reddish- 
brown color, with the thorax deeply punctured, and quarter of an inch 
in length. This insect is often seriously injurious to pine trees. An 
