EXTERNAL ANATOMY OF INSECTS. 481 



I am next to mention a part of the nose which me- 

 rits a distinct name and notice, which I conceive in some 

 sort to be analogous to the nostrils of quadrupeds, and 

 which I have therefore named the Rhinarium or nostril- 

 piece. I had originally distinguished it by the plural term 

 naves, nostrils; but as it is usually a single piece, I thought 

 it best to denote it by one in the singular. When I 

 treat of the senses of insects, I shall give you my reasons, 

 as I have before said, for considering this part as the 

 organ of scent, or connected with it, which you will then 

 be able to appreciate. I shall only here observe, that the 

 piece in question is in the usual situation of the nostrils 

 — between the nose and the lip. In a large number of 

 insects this part may be regarded as nearly obsolete; 

 or at least it is merely represented by the very narrow 

 membranous line that intervenes between the nose and 

 the lip and connects them ; which, as in the case of the 

 head of Harpali before noticed, may be capable of ten- 

 sion and relaxation, and so present a greater surface to 

 the action of the atmosphere. But I offer this as mere 

 conjecture. In the lady-bird (Coccinella) this line is a 

 little wider, and becomes a distinct Mhinarium ; as it 

 does also in Geotrupes. With respect to its insertion, 

 the rhinarium is a piece that either entirely separates 

 the nose from the lip, or only partially : the former is 

 the most common structure. It is particularly remark- 

 able in a New Holland genus of chafers (Anoplognat/ms 

 Leach). In A. viridicenens it is very ample, and forms 

 the under side of the recurved nose, so that a large space 

 intervenes between the margin of the latter and the base 

 of the labrum. In Macropus Thunb., of the Capricorn 

 tribe (Cerambyx L.), the nostril-piece, which forms a 



vol. III. 2 1 



