601* EXPLANATION OF THIi PLATES. 
PLATE XXI I." 
FIG. 
1. Mule genital organ of a Bombus. a. The male organ. 
b. The prehensor. Vol. IV. p. 57o', 580. 
2. Female ditto of the louse. (Swamm.) a. The oviduct with 
an egg passing through it. b c. The ovaries, d. The 
colleterium, or varnish secretor. e. The lower extremity 
of the oviduct. 
3, 4. Larvae as arranged in the body of two species of vivipa- 
rous flies. (Reaum.) Vol. I. p. 257 ; IV. p. 1/0. 
5. Interior of postpectus. Dynastes. a. Parapleura. 
b b b. Points of the postfurca. c. Its stalk. 
6. The medifurca of ditto, a. Base. b. Apex. 
7. Antefurca of ditto, a. Base. 
8. Mesothorax. Calandra. 
9. Mesophragm and appendage. Dynastes. a a. Pieces ad- 
jacent, b. Septula, c. The notch for the transmission 
of the intestines. 
10. Part of metaphragm, ditto, a. A kind of cupule affording 
a point of attachment to muscles, d. A deep notch for 
the intestines. 
11. Interior of the upper side of alitrunk of ditto, a. The 
cavity of the chest between the prophragm and meso- 
phragm. b. Ditto between the mesophragm and me- 
taphragm. c. Cupules that afford a point of attachment 
to some of the wing-muscles, d. Notch of the meta- 
phragm. 
12. Portion of the alitrunk of Meloloniha vulgaris, c. Cupule 
attached to the axis of the wings. 
13. Part of the postpectus of Dytiscus marginalis, to show the 
operculum. Vol. III. p. 578. 
14. Part of the metathorax of Mclolontha vulgaris, to show the 
metapnystega. Ibid. 572. 
15. The pseudocardia, or dorsal vessel of Stratyomis Chamce- 
leon. (Swamm.) 
* Vol. IV. Letted XLTI.j III. p. 580-. 
