586 



Wni. S. Marshall, 



of the anterior margin and the convexity of the posterior one is 

 present in both. 



In both of the wing rudiments there is now seen a slight indica- 

 tion of the markings which very soon become so pronounced. In the 

 specimen under consideration (Text figure VI) the markings are notice- 

 able only on the rudiment of the mesothorax. From an examination 

 of a number of specimens of about similar ages it is seen that as soon 

 as the markings appear they first begin at one end and then scatter 

 over the entire surface, this is true of both the rudiments. The ear- 

 liest appearance of the markings was noticed on the more posterior 



Text figure VI. 



Surface view of the mesotlioracic (to tlie left) and the metathoracic (to tlie right) wing rudi- 

 ments. Upon the former of these the markings are already present but none are noticed on the 

 latter. Dorsal above, posterior to the right. x 60. 



half or two-thirds of the rudiment although so few specimens were 

 examined for this point that it would not be well to make any State- 

 ment that this held true for all, The markings are seen as darkened 

 lines or stripes running transversely across the rudiment, they first 

 appear along the more ventral (later distal) margin but are not all 

 long enough to reach the other, more dorsal, one. Many of the mark- 

 ings are thickest where they touch the ventral margin of the rudiment 

 and from here run out to a point at the other end (Fig. 15). The mark- 

 ings grow more distinet on both rudiments and are nearly the same 

 m the one as in the other. Later other markings appear and these 

 are of two kinds: first, there are along the ventral margin other 

 malrkings similar to those already described except that they are 

 shorter and much more regulär in the distance from each other, and 



