Journal archives for November 2020

November 12, 2020

Larval Tenthredininae with medial dorsal spots

Pinkish-purple tenthredinine

Apparent eonymph: Body pinkish purple, lighter ventrally, darker above spiracles, with diffuse dark median line dorsally. Setae on annulets 2, 4 & 7, pale tubercles (usually?) on annulets 2 & 4. Annulet 2 with a median dorsal black spot, a lateral black spot just above spiracle, and one on each of the subspiracular(?) and surpedal(?) lobes. Head orange-brown with median black spot on vertex.

Host: Unknown.

Distribution: NJ, PA, VA.

Note: BG individuals without tubercles may represent a separate species, a different larval instar, or intraspecific variation. Setae on annulet 7 are not totally clear on specimens with tubercles.

Grey-blue, yellow ventered tenthredinine on hickory

Late-feeding stages: Body greyish blue above spiracles, yellow below, prothorax with yellow collar behind head. Abdominal segments with median dorsal black spot spanning annulets 1 & 2, annulet 2 also with lateral black spot just above spiracle. Four black spots above each proleg: one below spiracle and one on each of the postspiracular, subspiracular, and surpedal lobes. Head bluish grey and pruinose(?), yellow below eyes.

Host: Carya sp., C. ovata.

Distribution: WI, IA, IL, MD, PA.

Note: May be Macrophya, at least two species of which are known from hickory (M. cassandra, M. nigristigma). Dyar's (1898) description of the larva of M. externa (a synonym of M. cassandra) does not match: that species is mainly white. Presumed larvae of M. nigristigma are described in a manner strikingly similar to these (Middleton 1922). Per Middleton's description, earlier instars may have a more brownish colour with whitish undersides, while the prepupa turns a "faintly yellowish gray" in the darker areas, with black spots turning "faint gray".

White-dusted tenthredinine

Late-feeding stages: Body white, legs, prolegs, and ventral surface pale yellow. Median dorsal black spot spanning annulets 1 & 2; lateral black spot just above spiracle spanning annulets 1, 2 & 3. Diffuse black spot above proleg on surpedal lobe. Head bluish grey and pruinose(?), yellow below eyes.

Host: Verbesina, which has possibly been mistaken in some linked observations for nettle, false nettle, and maybe dogwood.

Distribution: NE, IL, MI, OH, PA, NJ, MD, WV, TN

Note: Same as those collected on BugGuide.

Posted on November 12, 2020 03:40 PM by skmonckton skmonckton | 0 comments | Leave a comment

November 14, 2020

Other larval tenthredininae

Pale greenish-grey with black spots on Solidago and/or Rudbeckia

Feeding stages: Body pale greenish grey, paler below spiracles, and a wide median dorsal line darker grey. Abdominal segments with following pattern of spots: subdorsal zone with small black spot on each of annulet 2 & 4, a large spot on annulet 7; supraspiracular zone with large black spot on annulet 2, small black spot on dorsal corner of second postspiracular lobe; ventral region with small black spot on spiracular area below spiracle, small black spot on ventral corner of second postspiracular lobe, and wide black spot on surpedal lobe. Older larvae may also have annulets 1-3 speckled with black dots within the dark median dorsal area. Head olive, dark behind eye, frons and vertex dark in an inverted mushroom shape.

Host: Solidago and/or Rudbeckia. One of the linked BG observations is from ironweed, but it's possible this was a misidentification (observation from June, prior to flowering of either plant).

Distribution: ON, QC, IA, WI, MI, OH, PA, VT, VA, TN

Note: May represent two closely-related species, one on either plant.

Posted on November 14, 2020 07:28 PM by skmonckton skmonckton | 0 comments | Leave a comment

November 17, 2020

Larval Nematinae

Pristiphora cf. cincta on Prunus, Crataegus

Late feeding stage: Body laterally faintly pinkish-orange, median longitudinal dorsal band dark, fading posteriorly. Each abdominal segment with a large yellow subdorsal blotch and a cluster of small dark spots below spiracle. Head brown with dark line extending backward from eye, median dark line from clypeus to vertex, these marks continuous with large dark spot on vertex covering most of dorsal part of head.

Hosts: Prunus serotina, Prunus virginiana, Crataegus, ?Amelanchier.

Distribution: BC, OR, MO, ON, PA.

Note: Strongly resembles Pristiphora cincta, which is recorded from Betula, Salix, and Vaccinium. That species has distinctly divided yellow blotches, with two large blotches/clusters subdorsally, and a diffuse cluster of smaller yellow spots laterally. The larvae noted here have a single large blotch subdorsally, with a diffuse cluster of smaller yellow spots below it.

Posted on November 17, 2020 11:34 PM by skmonckton skmonckton | 0 comments | Leave a comment