166 SMITH ON HYMENOPTERA OF ARU ISLANDS. 



gins. Abdomen finely and closely punctured ; the third segment 

 strongly so ; a broad yellow fascia on the apical margin of the second 

 segment. 

 Hab. Aru. 



2. Alastor apicatus. A. niger; abdominis segmentis primo et se- 

 cundo aurantiaco-rubris ; alls fuscis. 



Male. Length 5 1 lines. Black; the head and thorax strongly punc- 

 tured; a spot between the antennae, the scape in front, and the 

 clypeus yellow ; the latter with a large black spot at its base, ante- 

 riorly deeply emarginate; wings fuscous; the tegulse with a rufo- 

 testaceous spot at their outer margins ; the tarsi and articulations of 

 the legs ferruginous. Abdomen bright orange-red, with the third and 

 following segments black ; the base rugose, the second segment finely 

 punctured, the rest much more strongly so. 



Hab. Aru. 



Group SOCIAL WASPS. 

 ram. VESPID^, StepJi. 



\. IscHNOGASTER IRIDIPENNIS. I. rufcsccnti-fuscus flavo varius; 

 vertice et metathorace nigris, alis subhyalinis et pulcherrime iridescen- 

 tibus. 

 Male. Length T\ lines. Head yellow, above the insertion of the 

 antennae black; antemige black, with the scape, basal joint of the 

 antennae, and the mandibles feiTuginous ; the flagellum obscurely 

 ferruginous beneath ; the clypeus produced at the apex into an acute 

 tooth. Thorax pale ferruginous ; the metathorax black, with a ferru- 

 ginous spot on each side in front ; the scutellum with a reddish-brown 

 spot in the middle, the postscutellum yellow and subinterrupted in 

 the middle; the sides of the thorax yellow anteriorly, the yellow 

 portion w^ith two black spots ; the legs slightly variegated with 

 yellow ; wings subhyaline and brilliantly iridescent, the marginal cell 

 with a fuscous cloud. Abdomen brown ; the petiole pale testaceous 

 at its apex and ferruginous beneath, longer than the head and thorax ; 

 the second segment has a yellow macula on each side, and, beneath, a 

 smaller spot on each side in a line with the side spots ; the first seg- 

 ment has its basal portion yellow beneath, and a blackish spot in the 

 centre rather behind the middle. 

 Hab. Aru. 



This species in many particulars agrees with the I. nitidipennis of 

 Saussure, but diff'ers in too many, I think, to be considered the same 

 species ; the second recurrent nervure is straight at the upper extremity, 

 then curved towards the margin of the wing, and again straight at its 

 lower extremity; the third submarginal cell is much wider than the 

 fourth. 



