upon lepidopterous larva-, die. 319 



Fig. 8, x 8 diameters. The left conical receptacle of the larva 

 of Dicranura vinula, as seen from the left side, with its flagelhvm 

 completely everted. Comparison with fig. 6 indicates that the 

 flagelhim curves towards the dorsal aspect of the larva. On the 

 dorsal side of the base of the receptacle the anal flap is seen, and a 

 tubercle (of which there are two) terminating in a bristle, and 

 made use of in removing the faeces. The base of the flagellum is 

 faintly coloured and transparent, so that the rest of the organ can 

 be distinctly seen passing through this part during introversion. 

 As introversion commences with the apex of the organ, the latter 

 is seen to enter the transparent portion when the pink part is 

 reduced to half its length. In the normal position of rest the 

 transparent base is also introverted, and the deeply coloured part 

 of the organ can be dimly seen lying in the semitransparent 

 receptacle. The latter is covered with black patches, each of 

 which bears a tubercle terminating in a bristle. 



Fig. 9, x 188 diameters. The apex of the flagellum of the larva 

 of Dicranura vinula, drawn so as to show the arrangement of its 

 structural details. From the base up to the horizon a — a the 

 superficial characters are shown ; the cuticle, which appears 

 smooth to the naked eye and with very low powers, is seen to be 

 prolonged into very numerous fine sharp short processes (c) ; these 

 are also seen in section above a — a, and they are shown to be 

 processes of the superficial cuticular layer. Between a — a and 

 b — b the hypodermis cells (h. c.) are seen from the surface, the 

 cuticle having been removed. Above a — a the cuticle is seen in 

 section around the rest of the structure, and it consists of the two 

 normal layers, a superficial cuticular layer, which is non-laminated 

 (s. I. c), and a deep cuticular - layer, which is finely laminated 

 (d. I. c.) Both are quite transparent in this organ, although the 

 former contains the black pigment in other parts of the larva. 

 The whole of the pink pigment is contained in the flattened hypo- 

 dermis cells (h. c), and, as indicated in the drawing, it is darkest 

 round the margins of the cells, and especially at their apices. 

 Above b — b a longitudinal section along the middle fine of the 

 organ is shown ; an oblique view of a transverse section of the 

 structures beneath the cuticle, through half the organ, being 

 represented hnruediately below b — b. The structures on the 

 left side of the drawing are alone shaded in the longitudinal 

 section. The hypodermis cells (h. c.) are seen to be flattened and 

 to overlap each other. Beneath the cells is a delicate layer (b, I.) 

 representing the thicker "dermal" connective tissues in many 

 other parts. Beneath this there is a space filled with blood in the 

 everted organ. Then follows the retractor muscle made up of 



