1883.] MR. J. WOOD-MASON ON THE FAMILY EMBIID.«. 633 



This remarkable position of the wings seems to be explained by 

 their having been gradually reduced till they became so small as no 

 longer to need a concentrated thorax such as is to be seen in fully 

 winged insects, and by the thorax having as gradually reverted to 

 its primitive condition in the larvae, and come to retain it per- 

 manently. In fact, as little by little the wings decreased in breadth, 

 and consequently in the breadth of their attachments, their two 

 somites appear to have increased in length behind them. Of their 

 having been reduced, and of their being probably in process of still 

 further reduction, the wings of two of the species bear the evidence 

 on the face of them in the shape of one or more rudimentary vein- 

 lets ; and one of the species, namely O. michaeli, has, according to 

 Mr. M'Lachlan's figure of it, narrower and more pedunculated wings, 

 and a more primitive thorax than the other, namely O. saundersii, 

 the wings of which are fully described and figured below. 



The species of the subgenus Embia would also seem to differ 

 amongst themselves in the breadth of the wings, some having been 

 described as having these organs broad, others as having them 

 narrow. 



The coloration of the wings is also remarkable. It is usually de- 

 scribed by systematists as "fuscous black" or "fuliginous," "with 

 four" or "five whitish streaks," as the case may be; but for my 

 purpose it will be better to describe it as hyaline with the [black 

 or] brown veins all so broadly bordered on both sides with pale 

 [black- or] brov/n-smoky as to leave only narrow streaks ot the 

 ground-colour visible. In addition to the microscopically minute 

 setse with which the whole wing-membrane is thickly and regularly 

 studded, other and much longer setse are present, having a definite 

 arrangement along the edges and in rows on the disk of the wings, 

 namely, one row on each vein, and one row on each side of each 

 vein along the margins of the brown bands, or three rows to each 

 vein. The advantage of describing the colour and clothing of the 

 wings in the way I have done will at once become evident when 

 I add that the brown bands with their triple lines of setse re- 

 main to mark the original courses of veins which have long since 

 disappeared, and are now only represented by minute tapering pro- 

 cesses jutting out from existing veins a short distance into the 

 wing-membrane. 



There is yet another point of interest about the wings. Professor 

 Westwood describes and figures the second or subcostal vein of both 

 pairs of wings as long and as anastomosing with the third or radial 

 vein near the extremity of the wing ; and Mr. M'Lachlan speaks of 

 the coalescent subcosta and radius ; and both in dried and alcoholic 

 specimens these veins under an ordinary lens really appear to have 

 this arrangement and development ; but when the wings are mounted 

 in spirit and viewed under tlie microscope, it is readily seen that the 

 subcosta is quite short, and that its inclination to the anterior mar- 

 gin is such that it would, if produced far enough, run into the costal 

 vein at a point situated a little beyond the middle of the wing. The 

 illusive appearance of the presence of two concomitantly and com- 



