Hylurgops palliatus (Gyllenhal) Screening Aid

From: Cavey, J., Passoa, S. and Kucera D. 1994, Screening Aids for Exotic Bark Beetles in the Northeastern United States. NA-TP-11-94. Northeastern Area: U.S. Department of Agriculture, Forest Service.

General Appearance in a Sample. Hylurgops palliatus (Fig. 3) superficially resembles other scolytids in the subfamily Hylesininae. Some of the more obvious characters are:

• elytral apex rounded, not excavated, and without marginal teeth.
• elytral basal margin raised with series of marginal flattened granules (crenulations) (Fig. 1).
• pronotum usually unarmed and with an anterior constriction (Fig. 6: Anderson 1989).
• head usually visible from above.
• In addition, H. palliatus has red-brown elytra, pronotum and legs; and a black underside.

Recognizing the Genus. Some members of the genus Hylurgops are difficult to distinguish from Hylastes (Wood 1982, Bright 1976). Fortunately, only one species of Hylurgops is known to occur in the eastern U.S., H. rugipennis pinifex (Fitch). This species and H. palliatus are clearly distinct from Hylastes in all or most of the characters presented in couplet 5 of the key, below.

Recognizing H. palliatus. Characters for separating  H. palliatus from scolytids known from the northeastern U.S. are assembled in the following key. Because the recommended lure, alpha-pinene, will attract many bark beetles, screening personnel should obtain a specimen of the target pest to help preclude unnecessary, repetitive use of the key.

Key to Help Screen Hylurgops palliatus (Gyllenhal)
from Survey Samples of Northeastern U.S. Solytidae (Coleoptera)
(Adapted from Wood 1982, 1986):

1.	Anterior margin of elytra a straight, transverse line, not raised or armed with a number of granules; elytral apex may be excavated, with or without conspicuous spines or teeth	Not Hylurgops
	Anterior margin of elytra raised and armed with a number of granules (Fig. 1); subfamily Hylesininae; elytral apex convex, not excavated, without conspicuous spines or teeth	See #2
2.	Eye completely divided (transversely, near middle)	Not Hylurgops	Figure 1. Raised anterior margin of elytron, Tomicus piniperda (Ll.) (From Passoa and Cavey 1993).
	Eye entire (Fig. 3)	See #4
3.	Pronotum armed with asperites on anterolateral areas (Fig. 2)	Not Hylurgops
	Pronotum without asperites on anterolateral areas	See #4	Figure 2. Pronotum of Ips sp., showing anterolateral asperites.
4.	Procoxae widely separated by an intercoxal piece that is at least half as wide as a coxa (Fig. 4)	Not Hylurgops
	Procoxae contiguous or narrowly separated by an intercoxal piece that is less than half as wide as coxa (Fig. 4b)	See #5
5.	Pronotum without a noticeable anterior constriction (Fig. 5), with uniform large or small punctures (rarely with large punctures and a few smaller); 3rd tarsal segment small,emarginate but not bilobed; declivital hairlike setae, if present, not longer than ground vestiture ( Hylastes)	Not Hylurgops	Figure 3. Hylurgops palliatus (Gyllenhal), lateral view.
	Pronotum with a noticeable anterior constriction (Fig. 6), and nearly equal numbers of small and large punctures on the disc; 3rd tarsal segment bilobed, broader; elytral declivity usually with sparse, uniseriate rows of fine, hairlike interstrial setae that are longer than the ground vestiture (Hylurgops)	See #6
6.	Larger 3.7-5.2 mm; scalelike vestiture of elytra from middle of disc to apex; interstrial raised scallops or tubercles confused, not uniseriate (Fig. 7a)	Hylurgops rugipennis pinifex (Fitch)
	Smaller 2.5-3.2 mm; scalelike vestiture of elytra present from base to apex, more numerous on apical third; interstrial tubercles in a single row (Fig. 7b)	Hylurgops palliatus suspect	Figure 4. Venter of scolytid prothorax, a. procoxae widely separated, b. procoxae nearly contiguous.

Figure 5. Typical pronotum of Hylastes (After Wood 1982).	Figure 6. Typical pronotum of Hylurgops (After Wood 1982).	Figure 7. Elytron of a. Hylurgops rugipennis pinifex and b. H. palliatus, showing interstrial tubercles.

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