enlarged, brood patch, November 15, 1962, MCT 3279; [Female] brood patch, two collapsed follicles, November 15, 1962, MCT 3280; [Male] testis 7 x 6 mm., November 15, 1962, MCT 3281; [Female] brood patch, egg in oviduct, largest ovum 6 mm., November 15, 1962, MCT 3286; [Male] testis 7 x 6 mm., November 16, 1962, MCT 3290; [Male] testis 3 x 2 mm., November 16, 1962, MCT 3294; [Female], November 16, 1962, MCT 3295; [Male] testis 6 x 3 mm., November 17, 1962, MCT 3297; [Male] testis 5 x 5 mm., November 17, 1962, MCT 3298; [Female], November 17, 1962, MCT 3299. 5.5 mi. SW Tenom: [Female], December 26, 1962, MCT 3538. Gum-Gum: [Male], October 4, 1963, ADG 290; [Female], October 5, 1963, ADG 294; [Female], October 5, 1963, ADG 295. This was the most common of all the spiderhunters, and was found at all localities. It was readily taken in mist nets. Unlike most birds, these spiderhunters become quite agitated in nets, and within a few minutes usually strangle themselves. From October 16 through November 11, I took several specimens 12 miles north of Kalabakan, but only one in breeding condition. On November 15, I moved 12 miles back to Kalabakan from an elevation of 600 feet to an elevation of 50 feet. As can be seen from the specimen-data, nearly all the females then collected either had nests with eggs or were approaching oviposition. The specimens were all taken in nets in an area approximately 200 feet square. On November 20 at the Brantian Estate a bird sitting on a branch six inches up in secondary forest jumped down to the ground and fed on unknown material. _=Arachnothera crassirostris=_ (Reichenbach): Thick-billed Spiderhunter.--_Specimen_, 1: Cocoa Research Station: [Female], 14.8 gm., August 9, 1962, MCT 2746. This spiderhunter was recorded on the basis of one specimen and one sight record. One seen in secondary forest would dart out from its perch on a limb, hover near the end of a branch, and then return to its perch. No flowers were visible and I assumed that the bird was catching insects. _=Arachnothera flavigaster=_ (Eyton): Greater Yellow-eared Spiderhunter.--_Specimens_, 9: Cocoa Research Station: [Female] imm., 36.3 gm., August 21, 1962, MCT 2789; [Female] imm., 38.4 gm., August 21, 1962, MCT 2790; [Female], 38.4 gm., August 22, 1962, MCT 2795; [Female] brood patch, largest ova 2 mm., November 27, 1962, MCT 3330; [Male], November 28, 1962, MCT 3359; [Male] testis 7 x 6 mm., November 29, 1962, MCT 3379; [Male], November 30, 1962, MCT 3395; [Female], April 27, 1963, ADG 66; [Female], April 27, 1963, ADG 67. This species was met with only at Quoin Hill, where it was common around the abaca and wild bananas. The primary diet seemed to be pollen, nectar, and spiders. I found it easy to differentiate from the next species in the field (see below).