180 PEOF. W. H. JACKSON ON THE 



Fig. 31 . A similar preparation to the preceding, but the fat-body is removed and all the main muscles, 

 leaving only some very fine transverse muscle-bands. The anastomosis of the transverse 

 trache;e of the right and left sides is shown, as well as the course of the larval oviduct. 

 Obj. a*, oc. 2, Zeiss, draw-tube in. 



Fig. 32. Portion of hypodermis and attachment of right oviduct of an active feeding caterpillar, od., 

 the solid oviduct with faint longitudinal striations and numerous nuclei, elongated parallel 

 to the axis of the oviduct. At its ventral end the oviduct passes into continuity with the 

 hypodermis. A fine clear filament with a few nuclei passes off from the oviduct near its 

 termination to the hypodermis. tr., a minute trachea. The hypodermis is seen in this surface 

 view to consist of a number of nucleated cells, with a small amount of transparent non-staining 

 intercellular substance. The amount of this substance is perhaps slightly exaggerated in this 

 drawing. The cell-outlines are irregular. Obj. D, oc. 2, Zeiss, draw-tube in. 



Plate XVII. 



The following figures, 33-46, are drawn under obj. aa, oc. 2, Zeiss, draw-tube in. 



Fig. 33. Enlarged view showing the median attachments of the two oviducts, the anterior pair of 

 vesicles in the eighth segment, and the posterior pair in the ninth, of a full-grown active and 

 feeding caterpillar. It is taken from the same specimen as fig. 29. od., the line points to the 

 right oviduct, which is attached close to its fellow, v., the ventral muscle-band of the eighth 

 segment ; there is a similar band in the ninth, r.m., the band of rectal muscles. To the 

 posterior pair of vesicles is attached on either side a pair of filaments, of which the anterior 

 contains a trachea. 



Fig. 34. A similar view taken from a quiescent caterpillar. 8, 9, the corresponding segments ; od., the 

 paired oviducts ; od'., the anterior part of the azygos oviduct. The anterior vesicle is no longer 

 paired ; its anterior end, b.c, is elongated and rounded, and forms the rudiment of the bursa 

 copulatrix ; its posterior end is more pointed and forms the rudiment of the receptaculum 

 seminis, r.s. ; the anterior vesicle is connected to the posterior, p.v., by the posterior section 

 of the azygos oviduct. The posterior vesicle is elongated, and there is a very distinct median 

 furrow. Its filaments are undergoing atrophy, r.m., the rectal muscles. Note the shortening 

 of the muscle-bands and segments. The azygos oviduct is for the most part a ventrally open 

 furrow at this time. 



Fig. 35. Lateral view of the same specimen from right side. Letters as before. 



Fig. 36. View from above of a specimen similar to that from which fig. 34 is taken. The rudiments of 

 the bursa, b.c, and the receptaculum, r.s., are more pronounced, but the posterior vesicles 

 appear to be somewhat retarded in development. Letters as before. 



Fig. 37. An abnormally elongated and pointed anterior vesicle from another similar specimen. 



Fig. 38. View from above, taken from a pupa one day old. The terminal nerve-ganglion with the 

 nerves it gives off is seen anteriorly and in the middle line. Immediately behind it is the 

 rounded apex of the bursa, b.c, and behind that again the elongated receptaculum seminis, r.s., 

 bent upon itself, gl., the right sebaceous gland derived from the posterior vesicle ; the 

 corresponding gland on the left is not lettered ; the two are parallel to one another. The 

 azygos oviduct is seen behind the bursa extending back to the sebaceous glands. 



Fig. 39. A lateral view of the same specimen from the right side. Letters as before. The bursa, b.c, 

 is pyriform ; the left sebaceous gland, gl., is seen arched upon itself, and its anterior end is 

 dilated. This dilatation is the rudiment of the future left sebaceous vesicle, od'., the azygos 

 oviduct, which has a considerable vertical depth. 



Fig. 40. View from above, taken from a pupa two clays old. Letters as before. The bursa copulatrix, 

 b.c, is bent backwards; the receptaculum, r.s., has become nearly straightened, elongated, and 



