473 EXTERNAL ANATOMY OF INSECTS. 



the genera Copris, Onitis, or Ateuchus, and you will see 

 the nose marked out in the centre of the anterior part oi 

 the face by two elevated lines, forming nearly a triangle 

 and bounded by the horn a . Or take a common wasp or 

 hornet, and you will find a similar space, though ap- 

 proaching to a quadrangular figure, marked out by im- 

 pressed lines b . In Rhagio and Sciara, two Dipterous ge- 

 nera, this impression is so deep as to look like a suture. 

 Between these lines, in those cases, is included what I 

 call the nose. As to substance, in general it does not dif- 

 fer from the rest of the head; but in the Cleridee it is 

 almost membranous. You must observe, that in all these, 

 what at first sight appears to be the termination of the 

 front, is not the nose, but the narrow depressed piece 

 that intervenes between it and the lip. With regard to 

 its clothing, it is most commonly naked, but in some ge- 

 nera it is covered with hair; in Crabro F. often with 

 golden or silver pile, which imparts a singular brilliance 

 to the mouth of the insects of that genus : M. Latreille 

 supposes that the brilliant colours of the golden-wasp 

 (Chrysis L.) may dazzle their enemies, and so promote 

 their escape c ; the brilliance of the mouth of the Cra- 

 bro may on the contrary at first dazzle their prey for a 

 moment, so as to prevent their escape. The form of the 

 nose, where distinct from the rest of the face, admits of 

 several variations : thus in the Staphylinidce and Cleridte 

 it is transverse and linear; in Copris it is triangular, with 

 the vertex of the triangle truncated ; in Vespa Crabro it 

 is subquadrate and sinuated. In many Heteromerous 



a Plate XXVII. Fig. 4. a. b Plate VII. Fig. 2. a. 



e Observ. Nouv. sup les Hymennptcres {Ann. du Mus.) 5. 



