ISSN 1911-2173










Antennal sutures with angulate peaks and valleys.

Lines dividing antennal club into three antnnomeres.

Figure shows two angulate sutures near middle of oval club.


Antennal sutures curved through multiple peaks and valleys.


Ridge or elongate tubercle at midline of frons (circled). Not part of epistomal tubercles.


Epistoma. Area of head immediately above mouth opening. The epistomal row of tubercles (circled) is immediately above the epistoma. Epistomal setae project downward from the epistoma.


A depression or shallow pit.

Portion of head between eyes. Extends vertically from epistoma to top of eyes.


Rows of parallel ridges at the posterior end of the female head (or par stridens, arrow) and on the inner surface of the pronotum used for stridulatory sound production. Observing this structure requires removal of the head.

See Lanier et al., 1991 for details about using this character system.


Ridge or elongate tubercle across midline of frons. Impunctate in some species, weakly raised and impunctate in other species.



Posterior-most part of elytra when elytra are closed (bottom of figure). Also the apical-most part of the elytra.

The apical (posterior) sloping part of the elytra. In Ips the declivity is concave with spines along the sides.

The basal (anterior) level part of elytra. Does not include laterally sloped interstriae 5 to 9, or declivity


One of the hardened anterior pair of wings. These together form the elytra, the longitudinally divided dorsal shell covering the posterior half of the beetle.

Declivital spine with two apices (like two spines fused at base).


Declivital spine with point at both apex and ventral side.



Without puncture-like depressions on the interstriae (here seen as broad pale transverse bands). Measured on interstriae 2 and 3 on middle third of elytra (box).

The area between major rows of punctures on elytra (arrow). In this image these appear as shining elevated horizontal stripes. One or more interstriae bear interstrial punctures in some species. Interstriae are counted sequentially from the midline of the beetle beginning between the suture and the first stria.

White rectangle shows area of elytral disc used for comparison of species.

Punctures on interstriae. Presence or absence of interstrial punctures is assessed on middle part of elytral discInterstrial punctures bear setae unless setae are broken off.


Declivital spine nearly parallel-sided on basal half, and strongly tapered at apex.

Declivital spine narrowed near base.

Synonyms = pedunculate, capitate.

With puncture-like depressions in integument. These bear setae (hairlike projections) unless the setae are broken off.


A horn-like outgrowth of the integument that is not separated by any groove or ridge.

Spines are present on the elytral declivity of all Ips species.

The largest rows of punctures on the elytra. In Ips these are interrupted or distorted at the declivity. Striae are counted sequentially from the midline of the beetle.

Punctures along the striae. Larger than interstrial punctures and positioned on strial groove.

The elytral suture is the line (or gap) at the midline of the beetle where the two elytra meet.


Declivital spine narrowed evenly to apex.

Synonym = acuminate.



A connected system of subcortical tunnels and chambers in which a group of Ips beetles reproduce and develop. Galleries are usually initiated by a male and one or more females.



The dorsal part of the prothorax. The prothorax is the segment  into which the head and first pair of legs are joined.


The small exposed dorsal part of the mesothorax between the anterior edges of the elytra and the posterior edge of the pronotum.

 Spine-like projections in cavities in the protibia. True spines are not separated from the integument of the tibia by any line or groove.