314 E- H. STRICKLAND. 



Berlin Zoological Institute, but no statement is made as to 

 whether conditions during development were quite normal. Hey- 

 mons concludes his paper by suggesting that the abnormal de- 

 velopment described above is due entirely to an accelerated 

 development of the histoblasts, but makes no suggestions as to 

 the cause of the acceleration. 



In 1903 Kolbe reported and figured an interesting case of 

 prothetely in the larva of DetidroHmus pini L. He received the 

 larva when in its fourth moult, at which stage it had the following 

 characters: 



1. The larval antenna? were replaced by elongate antenna? 

 showing simple primary division into about seven segments. 



2. The larval thoracic legs were replaced by three pairs of 

 jointed legs possessing all the adult parts, namely, coxae, tro- 

 chanters, femora, tibiae and tarsi. 



3. The mouth parts were modified. 



Kolbe points out that all these organs were in an immature 

 adult, or true pupal form, thus showing, it would seem, that the 

 development was quite normal, but simply accelerated. \Yinne- 

 guth succeeded in breeding from a similar larva an iidult which 

 hatched as a small male that w^as apparently quite normal except 

 for its dwarf size. These abnormal larva? were produced from an 

 artificially hatched generation kept indoors and from parents 

 which did not hibernate. 



Hagen ('72) gives an account of silkworm larva? obtaining 

 wings before pupation, which condition was accompanied by 

 other abnormalities as follows: The head was small and had two 

 small facetted eyes, and the thorax became modified but the 

 abdomen remained in the normal condition of a larva in the 

 fourth moult. The fore wings were long and narrow and rather 

 more gray than usual, while the hind wings were short and nar- 

 row. As this anomaly occurred frequently and was therefore 

 liable to be of economic importance, its causes were investigated 

 by Majoli who came to the conclusion that it was due to the 

 larva? being kept at a temperature above the normal. 



A case similar to that of Heymons was described by Riley 

 ('08) from another coleopterous larva, Dendr aides canadensis, 

 which \v.i> bred by a student at Cornell I'niversity. 



