HYMENOPTERA OF THE HAWAIIAN ISLANDS. 217 



transverso, antice vertical! ; segmento secundo vix 

 tuberculato-elevato, postice baud rufo-marginato. 

 Long. (5" ? II millim. 



Head closely set with large but shallow punctures; 

 thorax punctured as much as the head, but with the punc- 

 tures becoming more sparing backwards, the metathorax 

 strongly rugose. The first segment of the hind body is 

 rather closely and strongly punctured, very transverse and 

 somewhat abruptly vertical in front, the second segment 

 has fine and deep punctures at the base, which become 

 gradually larger and shallower towards the apex ; the seg- 

 ment itself only slightly approaches the tubercular form, 

 but, viewed from the side, is seen to have a decidedly 

 greater longitudinal convexity than the rest ; the following 

 three segments are punctured much as the apical part of 

 the second. The insect is black, with the following parts 

 red : the mandibles, a spot between the eyes, the tegulse, 

 two spots below the tegulae, the scutellum, the postscu- 

 tellum, the first segment of the hind body, a large spot on 

 either side of the second segment. These markings are 

 probably variable, as some of them, in one or other of my 

 two specimens, are more or less obscured with black spots 

 or clouds. The wings are shining fuscous, without any 

 coloured iridescence. The legs are blackish, with shining 

 fuscous pubescence. The apical joint of the antennae, in 

 the male, is obscurely testaceous. 



Very closely allied to 0. rubritinctus, Sm., but differs in 

 the colour of the wings and in the absence of a red hind 

 margin to the second segment of the hind body. Of 

 fifteen specimens of 0. rubritinctus in my collection not 

 one varies in either of these respects. 



Occurred on Kauai in August. 



