340 STATES OF INSECTS. (Jmago.) 
it was mistaken by Gravenhorst*, while it is of the usual 
form in the other sex. . 
The extremity of the abdomen or its anal segments 
and organs furnish 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, Pentatoma hemorrhoidalis, &c.® At 
other times little lateral teeth are added to this notch, as 
in another of the same tribe, M. Willughbiella*. 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*.. In Anthidium manicatum, an- 
other bee, the anus terminates in five spines®. In Celi- 
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‘. 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 
terminates in a jointed tail, not unlike a scorpion’s, at 
the end of which is an incrassated joint armed with a 
forceps®. In the common earwig (Forjficula 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 
@ Coleopt. Micropt. 16. 
> Mon. Ap. Angi. i. t. vii. f. 25. De Geer iii, 255. t. xiv. f. 8. 
* Mon. Ap. Angl. i. t. viii. f. 24. 
4 [bid. t. ix. Apis xx. c. 2. y.f.12. © Ibid. Apis **. c. 2. 8. f. 11. 
€ Ibid. t. vii. Apis **.c. lee. f. 11, 12 9.13, 14. 3. ' 
€ Prare XV. Fic. 12. De Geer ii. ¢. xxiv. £. 9,10. 9.4. xxv. 
rae 
