caterpillar cremaster

[Sunsol Daniels]

>The caterpillar uses the anal prolegs (rearmost set of false legs),
>which have microscopic hooks, to clasp onto the silk pad.  When the
>larval skin is nearly shed, the pupa "steps out" of the skin, which is
>still attached to the pupa by a ligament at the posterior end of the
>pupa, and attaches it's cremaster to the silk pad. 

Gerald,

I got an email that said it uses anal claspers.  Is that the same as anal 
prolegs?

Ligament at the posterior end?  Really?  We videotaped the "stepping out" 
and that is not what we saw.  Is it different for different species?  
Where can I read about this process?

Thanks.

Sally