88 Descriptions of Preparations. 



of the two pairs of ganglia, of which the symmetrical portion of 

 the stomatogastric system consists, in this as in most other insects. 

 The paired ganglia are connected with each other, with the cere- 

 bral ganglia, and finally with the nervus recurrens, which struc- 

 ture, however, together with the ganglia in connection with it, 

 constitutes in these and most other insects by far the most im- 

 portant part of the stomato-gastric system. 



In the abdominal region are seen six ganglia corresponding to 

 the six posterior ganglia of the Lepidopterous larva. The two 

 first of the six, which correspond to the two which become obsolete 

 in the butterfly, are more closely apposed to each other than are 

 any of the succeeding four. The last ganghon is more or less 

 cordiform, and larger than those which precede it, and gives off 

 nerves to the lower portions of the generative and digestive tubes. 

 The ovaries are of the kind called ' verticillate ^ by Miiller; and 

 consist of eight moniliform tubes on either side, which are connected 

 anteriorly with the dorsal element of the prothorax by means of a 

 suspensory ligament, made up of the fusion of filaments given off 

 from their apices ; and which inferiorly open upon the convex end 

 of a pear-shaped ovidueal infundibulum, as ordinarily figured. The 

 infundibula of the two sides which may be seen, when undistended, 

 to have the egg-tubes inserted laterally as in other Orthoptera, pass 

 beneath the terminal nerve structures and the ^oviscapt^ to form a 

 common vagina, which opens in the interval between the eighth and 

 ninth abdominal segments. Immediately posteriorly to the last 

 nerve ganglion, in the angle limited by its branches, we may see 

 with a lens the receptacula seminis, which take the shape of two 

 short contorted coeca, one of which is rather larger in calibre than 

 the other, and which open by means of a single short duct in the 

 sternum of the ninth segment. The ^colleteriaF or '^sebaceous^ 

 glands, which consist of numerous delicate tubules of much greater 

 length than the receptacula seminis, open by two ducts in an 

 orifice upon the sternum of the tenth segment. The sternum of 

 this segment developes the smaller and inner processes of the 

 * oviscapt/ whilst that of the ninth developes the elongated ex- 

 terior pieces of that apparatus ; and as the lateral anal valves re- 

 present an eleventh segment, we have thus the typical number of 

 the segments of the Arthropodous abdomen made up. The recep- 

 taculum seminis is ordinarily in insects an azygos vesicle, and it is 



