STATES OF INSECTS. 341 



The extremity of. the abdomen, or its anal segments 

 and organs famish a variety of sexual characters. Some- 

 times the last dorsal segment is emarginate in the male, 

 and not in the female ; as in Megachile ligniseca, one of 

 the leaf-cutter bees, Cimex hcemor?7ioidalis, &c. a At 

 other times little lateral teeth are added to this notch, as 

 in another of the same tribe, M. Willughbiella b . Again, 

 in other males, both the ventral and dorsal anal segment 

 are armed each with a pair of teeth or mucros, as in 

 Chelostoma maxillosa c . In Anthidium manicaium, an- 

 other bee, the anus terminates in five spines d . In Cceli- 

 oxys conica of the same tribe, in which this part in the 

 female is very acute, that of the male is armed with six 

 points e . In that singular Neuropterous genus Panorpa, 

 while the abdomen of the female is of the ordinary form, 

 with a pair of biarticulate palpiform organs attached to the 

 last retractile joint, or ovipositor, that of the male termi- 

 nates in a jointed tail, not unlike a scorpion's, at the end 

 of which is an incrassated joint armed with a forceps f . In 

 the common earwig {JForficula auricularia) the two sexes 

 differ considerably in their anal forceps: in one it is armed 

 with internal teeth at the base, and suddenly dilated, above 

 which dilatation it is bent like a bow : in the other it is 

 smaller, without teeth, grows gradually narrower, is 

 very minutely crenulate from the base to the end, and is 

 straight, except at the very summit, where it curves in- 

 wards. Misled by these and similar differences, Mr. Mar- 



a Mon. Ap. Angl. i. t, viii./. 25. De Geer iii. 255. t. xiv./. 8. 



b Mon. Ap. Angl. i. t. viii./. 24. c Ibid. t. ix. Apis xx. c. 2. y.f. 12. 



^Ibid. Apis **. c. 2. fi.f. 11. 



" Ibid. t. vii.Apis**. c. 1. *./ 11, 12. $ . 13, 14. $. 



{ Plate XV. Fig. 12. De Geer ii. I. xxiv. /. 9, 10. $ . t. xxv. 



