EXTERNAL ANATOMY OF INSECTS. 541 



quite covered by the shield. Thus the upper portion of 

 the eyes can see objects above, as well as their lower por- 

 tion those below. I might enumerate many other forms, 

 but these are sufficient to give you some notion of the 

 variations of this part. 



5. The prothorax is equally various in its sculpture ,- 

 but since in the Orismological table almost every instance 

 of it has its place, I shall here only notice it as far as it 

 is common to the whole tribes, genera, or subgenera. 

 The Scarabceidce of Mr. W. S. MacLeay are distin- 

 guished by a small excavation on each side of this part, 

 which, as has been before remarked a , furnishes an ele- 

 vated base for an internal process with which the ante- 

 rior coxce ginglymate. In Onitis and Phanceus, to these 

 excavations are superadded a pair impressed in the base 

 of the prothorax, just above the scutellum ; in Carabus L. 

 a longitudinal channel divides the thoracic shield into 

 two equal portions ; and many genera of that great tribe 

 have in addition, at the base on each side, one or two 

 excavations or short furrows. Elophorus F. has on this 

 part several longitudinal channels, alternately straight 

 and undulated. Generally speaking, in Carabus L. the 

 prothorax has no impressed points ; but in one or two sub- 

 genera of Harpalidce (Chlcenia &c.) it is thickly covered 

 with them. In numbers of Locusta Leach, the part we 

 are considering is what Linne terms cruciate, being di- 

 vided into four longitudinal portions by three elevated 

 lines, the intermediate one being straight, and the late- 

 ral ones diverging from it both at their base and apex, so 

 as to form a sinus or angle b . In certain Acridce K. 



a Sea above, p. ."98. b Pt.ate XIII. Fig. 17. 



