1957] Brown — Orectognathus and Arnoldidris 23 
Orectognathus sarasini Emery 
In my Orectognathus revision of 1953, I followed Emery 
in recognizing 0 . sarasini as a distinct species, although 
it seemed from the original description that there was 
not much difference from antennatus. Wilson has now 
taken good series referable to sarasini in different localities 
in the southern half of New Caledonia. The material is 
divided between two distinct color forms, which, however, 
have the same measurements and the same general struc- 
ture: TL 4. 2-5. 3, HL 1.07-1.26, HW 0.81-1.00 (Cl 76-79), 
ML 0.64-0.71 (Mi 59-60), WL 1.12-1.31 mm. (workers). 
A female from series No. 115 measures: tl 5.6, hl 1.24, 
HW 1.04 (Cl 84), ML 0.69 (Ml 56), WL 1.40. A male 
measures: tl 3.7, hl 0.69, hw 0.74, wl 1.26 mm. (Series 
No. 115). 
This species is like O. antennatus, from which it differs 
only by the minor features cited in the key; the greater 
development of the humeral and anterior mesonotal pro- 
tuberances is a relative character, difficult to appreciate 
without comparison direct of material of both forms. 
As Wheeler suggested, it is entirely possible that anten- 
natus and sarasini are conspecific, but in the absence of 
objective criteria for their true relationship, it seems best 
to continue to distinguish them as arbitrary species, espe- 
cially in view of the possible complications next discussed. 
Emery described O. sarasini from Mt. Canala, New 
Caledonia. Wilson has seen type material, and affirms that 
it corresponds to a color form that he took, not at Canala, 
but at Mt. Mou and Le Chapeau Gendarme, which is 
concolorous clear ferruginous yellow, with only the legs 
lighter yellow (Mt. Mou: Nos. 115, 141; Le Chapeau 
Gendarme, No. 91 and Berlese samples). At and around 
Ciu, on the approaches to Mt. Canala, Wilson collected 
several series at about 300 m. altitude (Nos. 251, 289, 
observation colonies cc and ee, berlesates) in which the 
color of the workers is strikingly different: the color 
differs from that of sarasini in that the alitrunk and 
dorsum and sides of the head (except occipital lobes and 
sides of clypeus) are piceous, appearing black to the 
