276 THE CANADIAN ENTOMOLOGIST. 



apex, but only slightly irregular basally, without lateral spots, the punc- 

 tures strong and close-set basally and apically, virtually wanting medially 

 from side to side; elytra but little longer than wide, inflated basally, where 

 they are fully a fourth wider than the prothorax, each with fifteen coarse 

 and deeply impressed strire, which are only moderately coarsely but very 

 closely punctate, the green metallic spots less developed than in 

 tessellation, the sutural interval evenly dark to within a short distance of 

 the apex, where it fades ; outer spot of the second row resolved into two 

 small elongate dashes, the third row resolved into five elongate spots ; 

 under surface blackish-brown, the abdomen paler. Length, 8.5 mm.; 

 width, 5.2 mm. Texas. 



This is by far the largest species of the genus known to me. 



O. ellipticum, n. subsp. — Similar to tessellation throughout but larger 

 and more elongate, the elytra of a more pointed ogival outline behind; 

 head similar in coloration and sculpture, except that the (ew basal punc- 

 tures are finer ; prothorax much less abbreviated, but little, though 

 obviously, more than twice as wide as its median length, similar in colour 

 and sculpture, except that the punctures are much finer ; elytra similar in 

 general form and sculpture but less abbreviated, the sutural dark vitta 

 not enlarged before the apex, but gradually disappearing without the least 

 dilatation near the tip ; outer reniform spot of the second row almost 

 divided ; outer part of the third row resolved into a long and a short dash. 

 Length, 7.0 mm.; width, 4.3 mm. Rhode Island. 



Very closely allied to the more western tessellatum, and probably 

 more in the nature of a subspecies ; the comparisons are drawn from the 

 female in each instance. 



0. brevifienne, n. sp. — Form and sculpture nearly as in robustum, 

 Horn, but differing in maculation and in its smaller size ; head pale, the 

 base throughout the width, and extending narrowly along the eyes to their 

 middle and with two obtuse median spurs, metallic-green, the green areas 

 alone punctate, the punctures moderate ; prothorax fully two and one- 

 half times as wide as long, strongly trapezoidal, with evenly-arcuate sides 

 almost continuing the sides of the elytra, having, rather behind the middle, 

 a large transverse medial and at each side a small green spot, the former 

 broadly continued to the apex, also continued almost or quite to the base 

 at each of its ends and in the middle, the punctures strong and close-set 



