INSECTS OF NEW BRUNSWICK. 25 



near the tip ; but the track of the vein beyond the tip of the mediastinal is of course 

 conjectural. 



At a little beyond the end of the first third of tlie wing, it emits at a considerable 

 angle an inferior branch, which, at about half way from its base to the tip of the 

 mediastinal, or at just about the middle of the wing, begins to curve, so as to assume 

 a direction parallel to the main vein, and at the same time forks ; this whole branch 

 is very faint, and is almost effaced at the fork next which the wing is fractured. 

 To judge from the course of the other veins, one and only one of the offshoots of 

 that branch is again simply forked ; which, it would be impossible to say ; but the 

 upper offshoot (with its upper fork, if it divides) most probably runs sub-parallel to, and at 

 considerable distance from, the main scapular vein, very gradually appi'oaching it, 

 especially apically where it curves downward, until it terminates, probably at the 

 very apex of the wing. The sketch in fig. 5, however, rejjresents the lower branch 

 as forked, at a little past its middle ; there can be little doubt that the branches impinge 

 upon the margin at about the distance apart that is indicated, or at a little less distance 

 apart than the branches are seen to abut on the fragment of the lower margin which is 

 preserved. The only question is concerning the basal attachment of the vein which 

 strikes the border the second below the scapular vein itself ; if not attached as represented 

 in the plate, it originates from the branch of the scapular vein at probably a little less 

 than half the distance between its first forking and the apex. 



The vein lying next below this, and which appears on the plate (fig. 5) to have 

 a double attachment to the scapular vein, seems to be the externomedian vein. That 

 its basal half, like that of the preserved portion of the scapular branch, is very faintly 

 indicated on the stone seems due to some accident of preservation, for its aj)ical 

 branching part is distinct. It appears to originate from the scapular vein at a little 

 more than half way from the base of the wing to the origin of the scapular branch ; 

 its basal portion must therefore be either connate with the scapular vein, or be so 

 closely connected with it by the accidents of preservation as to be inseparable from it. It 

 diverges from the scapular at the same angle as the scapular branch, is very soon 

 connected with the adjacent vein below by a short cross nervule of unusual distinctness, 

 bends outward a little beyond this cross nervule, and at an equal distance beyond is 

 again bent to its fomier course ; here it is connected to the scapular vein by a faint 

 oblique cross vein, which is almost exactly continuous with the subsequent part of the 

 externomedian, and reaches the scapular vein directly above the distinct cross vein 

 above mentioned ; thus giving the mediastinal vein the appearance of having a double base, 

 and enclosing between its basal attachments an elongated subrhomboidal cell. Beyond 

 these basal divisions the vein runs in a straight oblique course to just before the 

 centre of the wing, where it forks widely, the upper branch being simple and excepting 

 for a gentle arcuation at its base nearly straight and a little more longitudinal than 

 the main stem ; the lower branch nearly continues the direction of the main stem, 

 and at a little less than half way to the margin forks, again widely, but symmetrically, 

 the offshoot being simple, the upper again forked half way to the margin, the final 

 upper fork being nearly horizontal and striking the border in the middle of the apical 

 half of the wing. 



