96 



then the caterpillar acquires secondary setae which are so short 

 and homogeneous that it seems to be naked. 



Smerinthus tiliae. 



Material in alcohol. July 1915. Plate IV, Fig. 2a, h. 



Instar /. Length 3 mm. 



The head is very large. Besides the tubercula described below, 

 the whole body and the caudal horn too, are covered with irre- 

 gularly plUced small setae, the length of which is + 50 ^a. With 

 a low power it looks as if they are bifurcated at the end as has 

 been figured by Sharp (II, p. 359) for instar / of Etichloe carda- 

 mines and by Packard (1905) for that of Ceteromia amyntor. 

 Highly magnified they appear to consist of a couple of bigger 

 rays and a number of thinner ones, all protuding from the 

 upper part of the seta. The whole thing might be compared 

 with an umbrella turned upside down of which some of the ribs 

 are thicker than the other. Plate IV, fig. 2a. 



The primary tubercula are not black in reality : the black in 

 the figure is only intended to draw attention to them. 



Prothorax. There are s. dorsalis, s. subdorsalis, s. supmstigmalis 

 or s. dorsolatendis, as it stands a little lower than one might expect 

 at first sight, s. prostigmalis and s. in frastig mails , two s. basales 

 placed next to each other, some smaller s. pedales. 



Mesothorax and Metathorax. S. dorsalis, s. suprastigmalis or 

 s. dorsolateralis, s. j^^'ostigmalis, two s. basales, a few smaller 

 s. pedales. 



Abdomen 1. S. dorsalis, s. subdorsalis, s. suprastigmalis, s.pro- 

 stigmalis, s. in frastig mails, two s. basales, one of which agrees 

 with s. 2)edalis. 

 Segm. 2 = 1. One s. basalls. 



„ 3, 4, 5, 6. 7 = 2 i. e. one s. basalis and one s. iiedalis. 



„ 8. We must consider the caudal horn as in the case of 

 Sphinx ligiistri. The skin is continued in unaltered con- 

 dition over the horn and bears the same umbrella-shaped 

 setae, for the rest as with 2. 



