OLBIOGASTER. 21 



Lobogaster, Phil. It differs from Bhyphus in the structure of the head (the eyes separated 

 by a broad front in both sexes, the occiput but very little developed), of the antennae 

 (the scapus short, the flagellum more filiform, &c), of the thorax and abdomen, also in 

 the venation (for the details compare above). 



Its relationship to Lobog aster is apparent in the structure of the abdomen, of the 

 antennae, and in the venation. The differences, however, are : — 1, the eyes are glabrous 

 and not " longe hirsuti " as Philippi has it ; 2, the bifurcation of the second and third 

 veins takes place some distance before the anterior cross-vein, and is not coincident with 

 that cross-vein; 3, the difference in size, both species of Lobog 'aster measuring 17-18 

 millim. in length, while the species of Olbiogaster are about half as long. Without 

 taking notice of the difference in the colouring, which is merely specific, I will mention 

 some minor discrepancies between my specimens and Dr. Philippi's description: the 

 face is slightly convex, but not " projecting like a bladder ;" the hairs on the face are 

 short and inconspicuous, and it cannot be said to be densely beset with long bristles 

 (" mit langen Borstchen dicht besetzt "). Philippi speaks of " ein Paar Borstchen 

 liber den Ocellen," which I do not perceive in Olbiogaster ; his figure (incorrectly 1) 

 represents a quantity of long hair on the front and vertex. The first abdominal segment 

 is described as " lang behaart " in Lobogaster, which is not the case with my specimen. 

 Philippi counts twelve joints in the antennae of Lobogaster; Schiner sixteen. I rather 

 believe the latter, as both Bhyphus and Olbiogaster have the same number. 



The difference between the venation of Lobogaster and Olbiogaster I have explained 

 above. That the venation of Lobogaster is exceedingly like that of Bhyphus, is very 

 easy to perceive in comparing the latter with figure 16 b of Philippi (not the principal 

 figure 16, where the venation is given incorrectly). When Schiner (Reise d. Novara, 

 p. 23) discovers differences between both which do not exist, it is the result of a most 

 unnatural interpretation of the homology of the veins, in consequence of which the 

 second vein (his Badialader) is said to be entirely wanting, and the fork to be formed 

 by the third vein alone (his Cubitalader)\ 



My statements are based on a specimen from Costa Rica, three (male and female) 

 specimens from Porto Rico (in the Berlin Museum), and the type specimen of Bhyphus 

 tceniatus, Bellardi, Saggio &c. Append, p. 5, fig. 5, which is a male Olbiogaster. 



1. Olbiogaster cognatus, sp. n., $ . 



Reddish-yellow. Head black, except the mouth-parts and the first joint of the antennae, which are reddish- 

 yellow : the face is dark brown in the middle, yellow on the sides ; antennal flagellum black ; front 

 above the antennae silvery, wbich colour is bounded by a straight line, running a little below the anterior 

 ocellus. Thorax shining reddish-yellow, with a scattered yellowish pubescence ; pleurae likewise shining, 

 except a spot, in the shape of an elongated square, above the sterno-pleural suture, which is semi opaque, 

 and in an oblique light shows a whitish, almost silvery reflection ; a brownish spot in front of the root of 

 the wings. Halteres reddish-yellow. Abdomen reddish-yellow, of a slightly paler shade than the thorax ; 

 the whole surface clothed with a golden-yellow, appressed pubescence ; segments 1-4 with a brown spot 

 in the anterior corner of each segment, the one on the first segment the smallest, on the other segments 



