418 TRANSACTIONS OF THE 



guished by the cylindrically-conic thorax, more elongated body, 

 and narrow, transverse mentum, which is widely emarginated, 

 without a conspicuous inner division, but in other respects much 

 resembling Cicindela. A genus has been lately formed by Mr. 

 Latreille, under the name of Therates, for an insect of the South 

 Sea Islands, which Fabricius had named C. lahiata. This has a 

 strikingly discrepant peculiarity in the form of the intermediate 

 palpi, which are abbreviated into a spine-like process. Manticora 

 includes two species, indigenous to the Cape of Good Hope, 

 which resemble Cicindela by the form of the mentum, in which 

 there is scarcely any difference; the jaws also are similar, and the 

 mandibles not unlike ; but a good distinctive character rests in 

 the palpi, of which the posterior are larger than the intermediate 

 ones; the abdomen also is somewhat pedunculated, and embraced 

 each side by the elytra. The last proximate genus which I shall 

 notice, is that of Megacephala, of which at least two species, the 

 Carolina and Virginica, are natives of this country, and are 

 principally found in the Southern States. In this genus, as in 

 those before adverted to, there is no difficulty in pointing out 

 good and substantial characters, by which [ 405 ] it may be read- 

 ily known ; the anterior palpi are elongated, and reflected, not 

 equal to the intermediate ones, as in Cicindela; the inner divis- 

 ion of the mentum is much shorter and the front of the head 

 convex. 



Having thus noted the differences existing between this genus 

 and each of its neighboring genera, I shall next proceed to lay 

 down its characters, distinguishing them into Essential, Artifi- 

 cial and Natural, for the first of which the preceding remarks 

 will furnish materials ; and finally, I shall endeavor to describe 

 the species with such accuracy and detail, that they may be 

 readily known. 



[Vol. I. 



