1922.] 153 



preceding row, being placed alternately to these. My friend, Mr. Hugh 

 Main, has since sent me an exactly similar batch on a hazel-leaf. 



The larva exists in live instars, and can be recognised by its 

 ochreous colour marked with bronzy black, and especially by the narrow 

 black arches that appear in the connexivum. The ochreous ground- 

 colour appears most distinctly at the anterior angles of the prothorax ; 

 in other parts it is very much obscured by black punctures, or by large 

 patches of bronze-black or greenish-bronze. The black punctux-es and the 

 metallic patches preserve their colour in the cast skin, but the ochreous 

 ground-colour becomes in the slough much paler. This is due to a 

 difference in the position of the pigments, which seems to be pretty 

 general in the family, viz. that shining and metallic colours are quite 

 supei-ficial, whereas dull colours belong to the deeper layers of the skin, 

 and are not shed at the ecdysis. It is curious also that the metallic 

 reflexions become more intense with each successive instar, but entirely 

 disappear at the last moult, leaving the imago of a plain brown colour 

 with a bright red tip to the scutellum. In the younger instars, again, a 

 very distinct ochreous ring is seen in the middle of the black tibiae ; but 

 by the time the last stage is reached, the ground-colour of the tibiae has 

 become largely tinged with reddish, and the ring has disappeared, while 

 the adult insect has entirely red tibiae. This same presence of a pale 

 ring in the younger stages, followed by its entire disappearance in the 

 adult, is seen even more markedly in Picromerus hiclens L. Another 

 curious feature that is revealed in the course of development is that the 

 lateral pronotal angles, which are so prominent a characteristic in the 

 the fully-grown insect, do not appear till the last larval instar, and there 

 is nothing in the early stages to suggest the possibility of such an 

 outgrowth. 



While we are on the subject of the prothorax, it may be as well to 

 point out the curious way in which in the imago that part of the insect's 

 anatomy is, in the majority of the Hemiptera, constructed, especially as 

 P. rujtpes well exemplifies the peculiarity. The dorsal and sternal parts 

 of the segment are very unequal, the sternum being shortened as much 

 as possible, so that there is only just room for the attachment of the small 

 pair of coxae, while the dorsal tergite forms a large plate extending 

 backwards and covering nearly a third of the whole body's length. This 

 chitlnous plate is almost the whole of the segment that exists above, and 

 it immediately overlaps the next segment without being attached 

 thereto, so that the gi-eater part of its area simply lies quite freely on 

 the very solid mass beneath, which constitutes the mesonotum and 



