14 Mr. G. C. Champion and Dr. T. A. Chapman's 



gera is very close, the differences are — hairs rather more 

 pronounced, angulation of the rounded abdominal outline 

 above spiracle already quite evident, the subsegmental 

 groove terminating a little way above spiracles just above 

 a ridge, whence the sides of the abdomen are a little 

 flattened. In second skin, the prothorax is yellow. Eat- 

 ing groundsel (Senecio vulgaris). 



In second skin head black; prothorax yellow, without 

 raised margin ; hairs marginal, not dorsal ; black of abdo- 

 men underlaid by the transparent shining yellow of the 

 inner structures. 



In third skin, deep black, except the prothorax, which is 

 bright yellow, with posterior margins slightly and lateral 

 margins more raised ; supra-spiracular angle very marked. 

 This is due to the inter-segmental incision being wanting 

 at this point. The dorsum consists of a series of folds or 

 ridges. At the actual dorsum these are seen to be the 

 subsegments, two to a segment, the segmental fold being 

 deep, the inter-segmental one shallow ; but below this the 

 two ridges are exactly the same, high and rounded, and the 

 folds also the same, deep and sharp. Downwards both 

 stop sharply, but the true segmental incisions earlier than 

 the other, so that the subsegmental fold is longest and 

 seems the most important. The ridge against which they 

 terminate thus runs a zigzag course, and the position of 

 the segmental incision is unmarked by any line or groove. 

 Below this zigzag ridge the segmental incision arises again 

 suddenly and is well marked and deep. The segment 

 is here uniformly convex, with no subsegmental groove. 

 This portion of each segment is flat from above down- 

 wards, so that all taken together form a flat, lateral surface, 

 separated from the curved dorsum by the zigzag ridge. 



The larvae have a gregarious tendency, being found all 

 close together, though put into a pot anyhow. They have 

 a clear yellow thorax from early in first skin, contrasting 

 strongly with the metallic bronzy-black of the rest of the 

 surface: the underside also is paler and yellowish. The 

 larva has a shorter and broader abdomen than that of 

 0. vittigera. The divisions or rugse are deeper and more 

 pronounced, and the whole larva is and feels hard rather 

 than soft as that of 0. vittigera does. The two dorsal 

 rugae to each segment uniting in a definite fold above 

 the spiracle proceed downwards as a single raised rib 

 giving a definite subdorsal flange at the point of juncture, 



