Hormaphidinae (Mordvilko, 1908)

Martin, Jon H. & Lau, Clive S. K., 2011, The Hemiptera-Sternorrhyncha (Insecta) of Hong Kong, China-an annotated inventory citing voucher specimens and published records, Zootaxa 2847, pp. 1-122 : 30-32

Hormaphidinae — Nipponaphidini

Dermaphis undetermined sp. 1 (Fig. 20)

Large sample in BMNH (coll. Martin) from the brown-bark stems of Cyclobalanopsis championii on High West summit, HK Island. Colonies were protected by debris sleeves created by attendant ants. Mature apterae heavily sclerotic, black, covered by greyish secretion, but teneral specimens reveal taxonomic characters well. Despite the density of individuals in the collected sample, no alatae or alatoid nymphs have been seen. It is clear that this species is not one of the three currently placed in Dermaphis and is likely to be undescribed (pers. obs. and Masato Sorin, pers. comm.).

Microthoracaphis elongata Takahashi (1958)

see Neothoracaphis elongata (Takahashi, 1958)

Neohormaphis undetermined sp. 1 (Fig. 19)

Large sample of alatae and nymphs in BMNH, from Cyclobalanopsis championii from High West, HK Island [the same small tree as the Neothoracaphis undetermined sample, below]. Alatoid nymphs secrete curious glassy filaments dorsally (Fig. 19), resembling miniature fibre-optic bundles. This generic determination is tentative (Victor Eastop, pers. comm.). The genus Neohormaphis , and its type species, N. calva Noordam (1991) was described from Javanese samples that had been collected by van der Goot from galls on Distylium stellare (Hamamelidaceae) and from Quercus sp. (Fagaceae) . Noordam noted curious circular “button organs” sparsely and singly distributed on the dorsum of the fourth-instar alatoid nymph of N. calva from Quercus . The equivalent nymphal stage in the HK sample has distinct plates, each with several (larger) circular structures that appear (especially in lateral view) to match the button organs of N. calva : it is these groups of organs that secrete the glassy filaments referred to, above. The biology of this curious aphid will certainly prove to be very interesting, and it is most likely to be undescribed. N. wuyiensis Jiang et al. (2008) , described from China, appears to be intermediate between N. calva and this HK species.

Neothoracaphis elongata (Takahashi, 1958) / saramaoensis (Takahashi, 1935) group of species (Fig. 18) Slide-mounted vouchers in BMNH (coll. Lau), from Cyclobalanopsis neglecta at Black’s Link, and from C. edithiae at Tai Tam Country Park Management HQ (both HK Island). These differ from the undetermined species (below) in having the hind legs much paler than the body (a character of both N. elongata and N. saramaoensis , according to Takahashi), and the anterior two pairs of legs apparently fused with the venter; the shape of the abdominal plates also differs from the undetermined species. This species in life has its five pairs of secreted dorsal wax rods distinctly curved (Fig. 18).

Neothoracaphis undetermined sp. 1 (Fig. 17)

An intriguing aphid with numerous specimens in BMNH, from Cyclobalanopsis championii from High West and Black’s Link, HK Island: the High West host was the same small tree as for the Neohormaphis sample, above. We originally placed this aphid in the genus Microthoracaphis but this was, however, regarded as a junior synonym of Neothoracaphis by Remaudière & Remaudière (1997). As with the preceding species the apterous adults are extremely small, jet black and nestle amongst the leaf hairs, with teneral specimens needed to show morphological characters clearly; nymphs are pale but alatae have yet to be seen. This species differs from the preceding one in having its anterior two pairs of legs freer, its hind legs not paler than remainder of body, a row of crenulations present mesal to the body margin and its dorsal secreted wax rods almost straight. It appears likely that there is a suite of Neothoracaphis species on species of Cyclobalanopsis .

Quernaphis tuberculatus ( Takahashi, 1933)

A single apterous adult female (BMNH) was originally found amongst specimens of Neothoracaphis and Neohormaphis (see above), feeding on Cyclobalanopsis championii at High West, HK Island. Subsequently more apterae were found on the same host species from Black’s Link, the extremely irregular body outline clearly being caused by the immobile aphids growing amid dense and stout leaf hairs. The HK material differs from Japanese specimens in BMNH, also determined as Q. tuberculatus , in possessing considerably more numerous stout dorsal setae (exactly as described and illustrated by Takahashi, 1933). These specimens are extremely small, body length between 0.25 and 0.4 mm.

Reticulaphis fici (Takahashi, 1923)

Vouchers in BMNH, from Ficus superba , F. superba japonica and Ficus spp. A single Takahashi slide is in TARI (Shu-Pei Chen, pers. comm.), under an earlier combination, Thoracaphis fici , collected from HK in March 1940 with no host information. Extensive municipal plantings of Ficus rumphii in Macau are also heavily infested with this aphid.

Reticulaphis inflata Yeh & Hsu (2008)

Described from material from Taiwan and HK. Paratypes in BMNH, from Ficus microcarpa at Wanchai, HK Island, and a small sample from Pok Fu Lam Country Park .

Reticulaphis undetermined sp. 1

Single sample split between BMNH and PPRD, collected from Ficus hispida at The Peak. The colony was exceptionally large, with a heavy coating of sooty mould on the upper surfaces of leaves. The very small apterae (a few are sufficiently teneral to reveal most characters well) display similarities with R. asymmetrica HRL & Takahashi (1959) and R. mirabilis (Takahashi, 1939) . However, this undetermined species has only 8 pairs of stout submarginal setae that have rather serrate apices: Yeh et al. (2008) reviewed Reticulaphis and stated that all species possess 10 pairs of submarginal setae, but careful examination of specimens of this species confirms only 8 pairs.

Schizoneuraphis gallarum van der Goot (1917)

Single large sample in BMNH, from Litsea glutinosa at Sham Shui Po police post, Kowloon (coll. Lau). Three Takahashi slides are present in TARI (Shu-Pei Chen, pers. comm.), under the junior synonym Thoracaphis hongkongensis van der Goot (1918) , collected from an undetermined host in HK in March 1940 and referred to by Takahashi (1941c); another TARI slide bearing Takahashi’s writing on the label was collected in HK in 1924, the collector given as Silvestri.

Thoracaphis fici van der Goot (nomen nudum)

This species was listed from HK as “ Thoracaphis fici v.d.G. (M.S.)” by van der Goot (1918). The only details given were “some apterous females and larvae, observed on the underside of the leaves of Ficus benjamina .” Blackman & Eastop (1994) only list three aphid species from F. benjamina , one of them a greenideine: of the other two, Nipponaphis ficicola HRL & Takahashi is quoted as feeding on the bark of stems and twigs, not under leaves. The third aphid listed on F. benjamina is Reticulaphis distylii group. Whilst it is very possible that van der Goot’s manuscript species was a Reticulaphis , it seems curious that van der Goot didn’t then place it in Schizoneuraphis , where he had already described what is now Reticulaphis distylii (van der Goot) only a year earlier. Unless voucher material can be found in one of the Dutch collections, this record necessarily refers to an unknown taxon within the Nipponaphidini .

Thoracaphis hongkongensis van der Goot (1918) See Schizoneuraphis gallarum van der Goot (1917)