Recognition characters of some of the commoner 



Single distinctive character 



1. Forms in which the immature stages (commonly known as nymphs) 

 and are plainly visible upon the back. 



2. Forms in which the immature stages differ very greatly from the adults 

 internally and not visible from the outside, and having the legs shorter, rudi- 



3. Further characters of some common dipterous larvae: these are distin- 



