320 Mr. Poulton's notes in 1886 



several bundles arranged round an axial space containing a large 

 ganglion. The muscle bundles (r. m.) consist of striated fibres, 

 and they are surrounded by a sheath (in. s.), which must be highly 

 elastic. Occupying the axial space there is seen to be a ganglion 

 made up of large ganglion cells (g. c.) and nerve-fibres (n. /.). 

 The proportion of nervous to muscular tissue is seen to be very 

 large. 



Fig. 10, X 24-5 diameters. One of the eversible ventral glands 

 of the larva of Croesus septentrionalis, as seen in longitudinal 

 section. The gland is represented as almost completely everted, 

 the apex being still retracted. The layers are represented dia- 

 grammatically : (s. 1. c.) = superficial non-laminated cuticular 

 layer; (d. 1. c.)=the deep laminated layer; (h. c.) = the hypo- 

 dermis cells. The retractor muscle is shown at (r. m.) ; its fibres 

 are striated. 



Fig. 11, x 2 diameters. The head and four anterior segments of 

 the larva of Gonoptera libatrix, as seen from the left side in the 

 contracted state before pupation. The larva had been taken out of 

 its cocoon. Two large black patches are very conspicuous on the 

 second and third thoracic segments : no trace of these markings 

 was present in the larva before the cocoon was spun. The line 

 parallel with the dorsal contour of all segments except the anterior 

 thoracic is the subdorsal, which was present in the younger larva, 

 and still remains distinct. The black patches exactly cover the 

 pupal wings which are developed beneath. 



Fig. 12, x 10 diameters. A transverse section through the middle 

 of the second thoracic segment of the larva of Gonoptera libatrix, 

 showing the relation of the black patch indicated in the last figure 

 to the developing pupal wings. Only the right half of the section 

 is complete, the median line being indicated by the dotted line a — a. 

 The digestive canal is indicated at (d. c), the commissural strands 

 of the ganglionic cord at (n. c.) The pupal cuticle is represented 

 by (p. c), and the larval cuticle by (I. c.) The pupal wing (p. tv.) 

 is seen to be developing as a pouch-like diverticulum of the body- 

 cavity. The black patch (b. p.) is shown to be due to pigment in 

 the superficial part of the larval cuticle ; its extent is seen to 

 correspond with that of the rudimentary wing beneath. 



Fig. 13, x 188 diameters. A portion of the developing wing of 

 the last figure, together with the larval cuticle which covers it, 

 seen in transverse section. The larval cuticle consists of the two 

 normal layers, of which the superficial one (s'. V. c'.) is seen to 

 contain the whole of the pigment of the black patch, while the 

 lower lamellated layer (d 1 . I 1 , c'.) is coloured by staining reagents. 

 This high magnification shows that the larval surface is rough, 



