316 STATES OF INSECTS. 



the mandible, but than the head itself a . Many sexual 

 differences are observable in the mandibles of the va- 

 rious tribes of bees (Anthophila Lain). Thus, in Collelcs 

 Latr. the male mandible is more distinctly biclentate at 

 the apex than the female b : in Sphecodes Latr. and others, 

 the reverse of this takes place c . Where these organs in 

 both sexes are toothed at the apex, they often vary in the 

 number of teeth. Thus, the female of Megachile centime 

 cularis Latr. has four teeth at the apex of its mandible, 

 while the male has only two d . In M. Wittughbiella, 

 though the mandibles of both sexes have four teeth, yet 

 those of the male are sharp, and the two external ones 

 the longest ; while those of his mate are obtuse, and all 

 nearly equal in length e . In Anthidium manicatum. Latr., 

 the former has only three teeth, while the latter has five f . 

 The differences in this respect in the hive-bee have been 

 before noticed S; those of the humble-bees (Bombus Latr.) 

 are strikingly distinguished from each other ; the female 

 mandible being very stout and wide, constricted in the 

 middle, and furrowed on its outer surface ; and the male, 

 on the contrary, very slender at the apex, dilated at the 

 base, and without furrows h . 



Of all the organs of the head, none seem so little sub- 

 ject to sexual variation as the under-jaws (mazilUe) '. I 



a Christ. Hymenopt. i. xviii./. 2. 



b Man. Ap. Angl. i. Melilta * a. t. If. 5. $ . 7. <? . 



c Ibid. Melitta **. a. t. ii./. 6. ? . 7. <? . and **. b. i. m.f. 3. ? . 4. <y . 



d Ibid. i. viii./. 11. <j> . 12. J . 



e Ibid.'i. t.ym.f. 9. $ . 10. <?. 



f Ibid. Apis **. c. 2. /3. t. ix.f. 6. $ . 7. $, 



R See above, Vol. II. 125. Note h . 



h Mon. Ap. Angl. ubi supr. i. xiii./. 13. ^ , 14. j. 



j MacLeaj^ Hor. Enlomolos. i—, 



