Prionichilus xanthopygius (Salvadori): Yellow-rumped Flowerpecker.—Specimens, 7: Cocoa Research Station: ♂ testis 5 × 5 mm., 8.9 gm., August 23, 1962, MCT 2800; ♀ largest ova 3 mm., oviduct enlarged, 10.2 gm., September 13, 1962, MCT 2910; ♀ imm., 9.7 gm., September 13, 1962, MCT 2911; ♂ testis 3 × 2 mm., 9.5 gm., September 13, 1962, MCT 2912; ♀ imm., 7.0 gm., September 14, 1962, MCT 2920; ♂ testis 6 × 4 mm., vas deferens enlarged, September 26, 1962, MCT 2966; ♂, November 27, 1962, MCT 3344.
This species did not appear at Quoin Hill until August 23. The gonads of most of the adults taken from that time on appeared to be regressing from breeding condition, and several immatures were taken also, suggesting that the breeding season was over. The birds seemed to be attracted, with bulbuls, to the tree Trema orientalis.
Prionichilus maculatus maculatus (Temminck): Yellow-throated Flowerpecker.—Specimen, 1: 12 mi. N Kalabakan: ♂, October 19, 1962, MCT 3094.
I observed this flowerpecker once at Quoin Hill, in much-disturbed primary forest, but was unable to secure a specimen. Twelve miles north of Kalabakan it was found in primary forest.
Dicaeum chrysorrheum Temminck: Yellow-vented Flowerpecker.—I observed one feeding about 50 feet high among epiphytic plants in the moss forest 5.5 miles north of Tenom.
Dicaeum monticolum Sharpe: Black-sided Flowerpecker.—Specimen, 1: 5.5 mi. SW Tenom: ♂ testis 5 × 3 mm., December 17, 1962, MCT 3449.
I saw this flowerpecker once, in the moss forest above Tenom. Treatment of this species as monotypic follows the revision of Salomonsen (1961:17).
Dicaeum cruentatum (Linnaeus): Scarlet-backed Flowerpecker.—Along the seashore near Tawau this species fed in flowering trees. Males were pugnacious and persistently chased what appeared to be females.
Dicaeum trigonostigma dayakanum Chasen and Kloss: Orange-bellied Flowerpecker.—Specimen, 1: 5.5 mi. SW Tenom: ♂, December 23, 1962, MCT 3507.