Manchester Memoirs, Vol. Ixi. (iQi/), A'^;. !4. g 



For reasons which will appear later, we have removed it to 

 th2 genus Goldenbergia, Scudder (Proc. Amer. Acad., Vol. XX., 

 p. 172. 1885), as that generic name takes precedence of Micro- 

 diet ya (1Q06) and of Sagcnoptcra, a genus created by Hand- 

 hrsch in IQ06 (Die Fossil Insektcn, p. 72), for forms which are 

 indistinguishable from species of Goldenbergia. 



The wing fragment in the Stirrup Collection consists of 

 the distal half only, and is most excellently jjrcserved. Brong- 

 niart's figure is on too reduced a scale to do justice to what 

 •was one of the most beautiful of insect wings from the Coal 

 Measures. The wing examined In' him had a length of 80 mm., 

 with a breadth of 22 mm. 



The length of the wing fragment in the Stirrup Collection 

 is 56 mm., and its greatest diameter 28 mm. The length of 

 the complete wing must have been about Q5 mm., with a breadth 

 of 30 mm., so that it belonged to a larger insect than Brongniart 

 was aw^are of.* 



The wing fragment shows that the costal margin slopes 

 rapidly backwards to the wing apex, which is bluntly acute, 

 and narrower than in the ty])e figure. The wing apex might 

 be described as a bluntly rounded angle, formed by the union 

 of the inner and outer wing margins. The distal portion of 

 the sub-costa is a well-marked vein, which reaches the costal 

 margin at a point 2Q mm. from the extreme tip of the wing. 



The radius follows a course parallel to the sub-costa, cui-v- 

 ing inwards when beyond the point at which the latter reaches 

 the wing margin, and joining the wing margin at the outer 

 side of the wing apex. The radial sector was given off from 

 the radius at about the hrst third of the latter's length. It 

 diverges slightly from the radius, continuing as a single stem 

 until the distal third of the wing is reached, in which it gives 

 off four inwardly directed twigs, and ends on the- wing apex 

 in a short fork. The first or most proximal twig bifurcates 

 12 mm. from its point of origin, the two twigs diverging slightly 

 as they pass to the inner wing margin. 



The remaining three twigs follow a parallel course, passing 

 in a wide sweep inwardly, so that only the two most distal 

 twigs and the end of the main stem reach the wing apex. 

 Brongniart's figure only shows three twigs arising from the 

 radial sector, the proximal one forking as in the j)resent case. 



The main stem of the median vein must have ])assed 

 almost straight out from its point of origin to near the middle 

 of the wing, where it divides, giving off a wide, sweeping, 

 outward loranch. which remains simple, and an inner shorter 

 branch, having a somewhat similar curve, and forking into 

 two t^qual twigs, the proximal of which forks again before the 

 wing margin is reached. 



*Prof. A. Lamccrc, of the 1 'nivcrsity of l^russcls, has suK^ested to 

 mo that this increased size mav be a sexual difference. 



