273 



feature, whilst for the colour of the wings of Lepidoptera T refci- 

 to J.F. VAN Bemmelen (1889— 191G), J. Botke (1916), J. II. de 

 Meyere (191G). 



The next study which is of great importanco for the know- 

 ledge of the setae is that of Packard (1890). Without paying 

 mueh attention to the arrangement of the setae, Packard especially 

 devoted himself to their different shapes. What struck him especially 

 with the Bombyces, was the intricate shape of the setae of the 

 full-grown caterpillars. He examined their ontogenesis and thereby 

 was led to the establishment of a series of types (1. c. p. 512 sqq.) 

 of tubercula and setae which are often used even now in des- 

 criptions. Packard's list, which has also been included in the 

 great work (1895) on the Bombyces, may be cited here: 



^A. Tubercles. 



a. Simple and minitte, due to a slight thickening of the hypo- 

 dermis and a decided thickening of the overlying cuticle; the 

 hypodermis contains a large unicellular gland either for the secre- 

 tion of the seta or for the production of poison. 



1. Minute piliferous warts (Most Thieid, Tortricid and Noctnid 

 larvae). 



2. Enlarged smooth tubercles, hearing a single seta. 

 (Many Geometrid and Bomhyc'me larvae). 



3. Enlarged, spherical tubercles, hearing a number of setae, 

 either radiated or subverticillate {Arctians^ Lithosians, Zygaenidae, 

 including some Glaucopinae). 



4. High, movable, smooth tubercles, having a terrifying func- 

 tion {Schizura^ Xylinodes^ Notodonta^ Nerice). 



5. Low and broad, rudimentary, replacing the „caudal horn" 

 (Choerocampa, the European Pheosia dictoea and dictoeoides). 



h. More or less spinulose or spiny (disappearing in some Sphingids 

 after stage J). 



1. Long and slender, usually situated on top of the eighth 

 abdominal segment, with microscopic spinules in stage /. (Most 

 Sphmgidae and Sesia). 



