HIPPOBOSCIDAE. 



13 



Aldrich records (as 0. confluens) specimens from Halcyon tutuilae, Tiituila, 

 Samoa, which in all probability belong to this species, and other specimens 

 from Halcyon sp., Philippine Islands, which in view of the host might well be 

 conspecific. 



Present record. — Six specimens, all males : one from Aplonis atrifusca, Apia, 

 Samoa, ll.xi.l924 ; three from Halcyon juliae, Espiritu Santo, New Hebrides, 

 25.vii.1925 ; and two from the latter host, Tanna, New Hebrides, ix.l925. 



Notes. — The identification of this species as 0. pusilla is based entirely upon 

 community of host and general locality, and it must be recognised that the 

 presence of 0. promiscua in the same region, and possibly on the same hosts, 

 causes an element of doubt. The length of the species is given by Speiser as 

 2-2 mm. The specimens available measure about 3 mm., but the difference is 

 to be ascribed to the fact that the earlier measurements were made from dried 

 and shrivelled material. 



Text- FIG. 2. — Ornithoica pusilla (Schiner), wing of same specimen as text-fig. 1. 



So far as the characters of the head and thorax are concerned, the present 

 species does not differ significantly from other members of the same genus, 

 which are represented in other material available. The wings also (text-fig. 2) 

 are of the common type. The trochanters of the hind legs, however, bear on 

 their posterior border a cluster of short, stout, black setae (text-fig. I, a), and the 

 apex of the posterior tibiae bears a distinct spur (text-fig. 1,6). 



The dorsum of the abdomen, in addition to the usual basal plate and the 

 paired apical plates, has only three transverse sclerites ; the ventral side lacks 

 the clusters of chitinous tubercles, which are conspicuous features of 0. promiscua. 

 It might be surmised that this difference in the number of tergal plates is a sexual 

 character, but such is not the case. In these characters the specimens before 

 me agree with an individual from Borneo, which I have considered possibly to 



