markings and attitudes of lepidopterous larvce. 327 



when the level of the oblique stripe is reached. By this enlarge- 

 ment of a single dot at the appropriate level in each aunulus the 

 oblique stripes and other vi^hite markings arise. The 8th stripes are 

 seen together as a V, and their constitution is shown to be similar to 

 that of the other stripes. The purple borders are very small at the 

 beginning of the stage, but the figure shows that this marking has 

 nothing to do with the dots (which are absent from it), but arises 

 as a darkening of the ground colom-. The annulation of the 

 segments is very distinct. 



Fig. 10, X 50 diam. — The extremity of a well-formed horn of a 

 larva of S. ligustri in the third stage, viewed from above. The horn 

 is covered with black tubercles (shagreen dots) terminated by minute 

 hairs, which are always directed upwards. The bifid tip is formed 

 of two rather larger tubercles with longer hairs. This feature is, 

 of course, much more pronounced in earlier stages. 



Fig. 11, X 188 diam. — A single tubercle (dot), seen in optical 

 section, from the side of the horn of the larva of Smerinthus ocellatua 

 at the end of the third stage. The hair upon the apex is forked. 

 The great majority are of this kind, but sometimes three or even 

 four prongs are found in this species ; and some hairs terminate 

 simply. The penetration of the base of the hair into the apex of 

 the tubercle can be just made out, as shown in the figure. The 

 hairs are transparent and colourless. 



Fig. 12, x '6 diam. — The head of the larva of S. ocellatus in the 

 third stage, as seen from the front. The larva was an extremely 

 yellow variety, even at this period. (It was a larva found upon 

 Salix rubra in the summer of 1884). The head is covered with 

 yellow shagreen dots (with hairs). These are arranged round the 

 margin as a yellow line in which they have coalesced, but are still 

 recognisable. The two dots at the apex of the head and the 

 summit of the marginal lines are bright red in colour, and greatly 

 enlarged (although they still retain the hairs). At this time they 

 form a very conspicuous feature. 



Fig. 13, x 2 diam. — The head of a whitish-green larva of 

 S. ocellatus at the beginning of the fifth stage, viewed from the 

 front. The red tubercles, which were so distinct in the last figure 

 (12), were also prominent in the second stage, and continued into 

 the fourth. At the close of this latter stage, however, the colour 

 becomes yellowish or orange. In this figure (13) it is shown that 

 the tubercles still retain the red colour upon their rounded 

 summits, but their relative size is much less, and their shape is 

 not conspicuous. 



Fig. 14, x 2 diam. — The head of a yellowish-green larva of 

 S. ocellatus, advanced in fifth stage (about 50 mm. long) when 

 looked at fi-om the front. In this figure the red has eutii-ely 



