EXTERNAL ANATOMY OF INSECTS. 669 



from base to apex 3 : in a species of Empusa (E. macro- 

 ptera), the four posterior ones are so distinguished only 

 on their posterior side b : others of this last genus, as 

 E. gongyloides, have an alary appendage on both sides 

 at the apex of these thighs c ; and another family, as 

 E. pauperata, have only one on the posterior side d . The 

 thighs of no insect are more remarkable for their elegant 

 shape, — tapering gradually from the base to the apex, 

 where they swell again into a kind of knee,; — than the pos- 

 terior ones of the locusts (Locusta Leach) ; each side of 

 these thighs is strengthened with three longitudinal nearly 

 parallel ridges, and the upper and under sides are adorn- 

 ed by a double series, in some coalescing as they ap- 

 proach the tibia, of oblique quadrangular elevations re- 

 sembling scales e . 



I shall next say a few words upon the spines and other 

 processes which arm the thigh. Those moveable ones of 

 Mantis which help to form a fearful instrument of de- 

 struction, have just been mentioned, and similar ones, but 

 less conspicuous, arm the intermediate thighs of Sicusjla- 

 vipes : other appendages of this kind are for a less de- 

 structive purpose — to keep the tibia when folded in its 

 place. This seems to be the use of the serratures and 

 spine that arm the thigh of Bruchus Bactris, or the 

 Hymenopterous genera Leucospis, Chalcis, &c. ; in Onitis 

 Aygulus a short filiform horn arms the humerus, and a 

 longer crooked one that of many species of Scaurus f . In 

 many Stenocori the thighs terminate in two spines, and 



a Stoll Spectres t. vii./. 25. b Ibid. t. viii./. 30. 



c Ibid, ubi supr. d Ibid. t. x. / 40. ^ 



e Plate XIV. Fig. 5. This appearance of scales on the thighs is 

 principally confined to this tribe. f Plate XXVII. Fig. 23. 



