markings and attitudes of lepidopterons larvce. 293 



larvae are seen from above. The darkening of the ground 

 colour in front of the oblique stripes takes place from 

 above downwards : in Sphinx lignstri it was in the 

 reverse direction (but the purple appeared in front of the 

 middle of a stripe). The Sphinx attitude of this larva 

 is somewhat geometriform, the last two and sometimes 

 three pairs of claspers being used, the others retracted 

 very completely. This is also true of the other stages. 

 On examining the hairs upon the shagreen dots with a 

 compound microscope (using a lens of about fifty 

 diameters) it is seen that nearly all of them are forked 

 at the tip. The fork generally consists of two prongs, 

 but occasionally of three or even four, and sometimes 

 the hairs end simply. With higher powers (200 dia- 

 meters) it is seen, in optical section, that the base of the 

 hair penetrates the apex of the shagreen tubercle (see 

 fig. 11, X 188, Plate VII.). The hairs on the red 

 tubercles (on the summit of the head) seemed to be 

 rudimentary, and were not forked in any larvse that 1 

 examined. The ends of the hairs often appeared as if 

 they were cut off short, while the sides were produced 

 into slight horns : this is evidently a form of two- 

 pronged fork. These appearances are found on the 

 hairs of the whole surface. I do not yet know how far 

 these facts about the hairs are true of all the other 

 stages. 



Stage IV. — The markings are similar to those de- 

 scribed in the last stage. The darkened ground colour 

 in front of the stripes has no dots on it, or only very 

 small ones. So also with the dark dorsal line, which 

 has a row of dots on each side of it, producing altogether 

 a very midrib-like appearance. Thus in a larva uniformly 

 dotted with white tubercles, the linear arrangement of 

 the tubercles produces white stripes, while their linear 

 disappearance produces dark lines. The red tubercles 

 are still present, and their colour tinges a few small 

 ones near to them. Towards the close of the stage 

 their colour becomes less conspicuous, and often inclines 

 towards orange. It is now noticed for the first time that 

 the first spiracle is concealed beneath a fold of the 

 contracted prothorax in the protective attitude. The 

 horn is still red and white. The hairs, which are so 

 minute over the general surface, are at all times much 

 longer upon the anal flap and last pair of claspers. At 

 the close of the stage the horn becomes light blue, but 



