334- STATES OF INSECTS. 



boides in neither. In Pelecinus Potycerator F., one of 

 the Ichneumon tribe, or an insect very near it from Bra- 

 zil, these thighs in the female are armed with two spines 

 underneath, which are not in the male. 



The anterior tibia in Scarabceus longimanus L. differ 

 remarkably in the sexes. In the female they are of the 

 ordinary shape, and serrated externally ; but in the male 

 they are very long, incurved, and without teeth or serra- 

 tures a . In the males of the genus Onitis F. they are bent 

 like a bow, and acute at the end ; but in the females they 

 are formed on the common type b . In Hisp.a spinipes F. 

 they are armed internally with a crooked spine c . But 

 the most extraordinary sexual variation of this joint of 

 the leg may be seen in the male of Crabro cribarius F. 

 and several other species of the same family, in which 

 these tibiae are dilated externally into a concavo-convex 

 plate, or rather have one fixed to them and part of the 

 thigh, of an irregular and somewhat angular shape d , 

 with numerous transparent dots, so as not badly to re- 

 semble a sieve : whence the trivial name of the species. 

 Rolander, who first described it, fancied that this plate 

 was really perforated, and that by means of it the animal 

 actually sifted the pollen ; but it is most probably for 

 sexual purposes. In another species, the plate is orna- 

 mented with transparent converging streaks. In the 

 bee-tribes (Anthophila Latr.) the posteriw tibia of the 

 working sex is generally bigger than the corresponding 

 part in their more idle partners : this is particularly con- 



a Oliv. n. 3. t. xxvii./. 27. £ . and t. \v.f. 27. <? • 

 b Ibid. t. vii./. 58. <?./. 57. $ . 

 c Ibid. n. 95. Hispa t. If. 4. Plate XXVII. Fig. 24. 

 d Plate XV. Fig. 3. 



