343 



Iininodiately aftor the moult on protliorax and segment 8 setac 

 whieh differ froni tlie rest. The plumose ones shorter than the 

 ordinary setae in instar III and IV. Those of segment 8 only 

 eome in instar /T' and are still very short. 



Whole life as caterpiUar is 45 — 55 days. Four monlts. 



I hope that these differences may give rise to new investigations. 



It also seems to me that the histological structure of these 

 setae and the manner of their origin within the more simply orga- 

 nized ones of the former instar, are worth while examining. 



I draw attention to the fact, that J. H. Kruimel in his inves- 

 tigations on the feathers of the Gallinae (1916) also found a 

 more composite structure in the successive "editions of feathers" 

 whieh appear after the different moults. 



Family Lasiocampidae. Fracker (1915, p. 103) thinks there 

 are too many setae to be able to describe them. Some genera 

 are characterised by a dorsal horn on segment 8. 



Dyar (1893 h) has described different kinds. 



Lasiocampa vuhi L., Plate XI, fig. 6, 7. 



M a t e r i a 1 in alcohol of the three last instars of the cater- 

 pillars (i. e. instar /ƒƒ, /F, F), collected at Groningen, in the 

 summer of 1913. 



Instar III. Length 27 mm. 



The whole body is covered with widely spread setae of about 

 '/a nim. long. The tubercula are black, have the form of warts 

 and possess many unfeathered setae, whieh are about 1 ^/.^ mm. long. 



Prothorax. No prothoracic shield, but there is an elevation between 

 the three following verrucae. This elevation, however, is not black 

 and the setae are as large as on the remaining surface of the body. 



There are: v. dorsalis, v. subdorsalis, v. suprastigmalis, placed 

 very high ; r. pyosticjmaJis^ v. hasah's, smaller r. propedalis and 

 v. postpedali^. 



