EXTERNAL ANATOMY OF INSECTS. 479 



beetles a it is rounded posteriorly : in Pelecotma, a new 

 genus in this tribe, related to Asida, there is a deep an- 

 terior sinus ; in Blaps the anterior margin is concave ; 

 in Cetonia h Brownii, and atropunctata (forming a distinct 

 subgenus), it is bifid: it varies in the ScarabceicLe, in 

 some being bidentate, in others quadridentate, and in 

 others again sexdentate, including the cheeks : in Myla- 

 bris, a kind of blister-beetle, it is transverse and nearly 

 oval ; in Lamia, a capricorn-beetle, it represents a paral- 

 lelogram; and in most Orthoptera it is orbicular: in TeU 

 tigonia F. it is prominent, transversely furrowed, and di- 

 vided by a longitudinal channel : in Otiocems K. it pre- 

 sents the longitudinal section of a cone c : in the Diptera 

 Order, with the exception of the TipulidcB and some 

 others, in which it unites with the cheeks, &c. to form a 

 rostrum, the nose in general, as to form, answers to its 

 name, resembling that of many of the Mammalia: in 

 some of the Asilidce it is very tumid at the end, and ter- 

 minates in a sinus, to permit the passage of the proboscis 

 to and fro : in many of the Syrphida, &c. it is first flat 

 and depressed, and then is suddenly elevated, so as to 

 give the animal's head the air of that of a monkey : in 

 some tribes, as Rhingia, Nemotelus, Eristalis, &c, in 

 conjunction with the cheeks itjbrms a conical rostrum: 

 in Tabanus bovinus, and other horse-flies, it terminates 

 in three angles or teeth. Many more forms might be 

 mentioned, but these will suffice to give you a general 

 idea of them. In size and proportions the nose also va- 



a Those beetles whose posterior pair of tarsi have only four joints, 

 and the two anterior five, are so called. 



b Kirby in Linn. Trans, xii. 464. /. xxiii./. 6. 

 c Ibid. xiii. t.'i.f. \.b. 



