Pupal suspension of Thais. 215 



that passes over the loop and encloses it in a short tunnel. 

 Sometimes it is quite fixed here, at others it can be drawn 

 through these tunnels and removed, if it is first cut. The 

 two places where these lappets are found are on the hind- 

 wing, and on the fore-wing just below the cell some little 

 way basal to vein 2. 



It is perhaps erroneous to say that the loop sinks into 

 the soft chitin, at least to say so may produce; the false 

 impression that there is something accidental about it ; it 

 is, however, a constant arrangement, and the lappets are 

 no doubt structures specially arranged for the purpose. 



To test this a larva suspended for pupation was treated 

 by cutting the loop away. It was seen very shortly after 

 pupation, before the pupa had quite assumed its permanent 

 form and was still very soft. The very striking fact 

 appeared now, that across the wings there was a very 

 distinct depression marked by a central linear mark, as 

 if the girth were present and indenting the soft pupa. 

 When the pupa had attained maturity with a firm skin, 

 this appearance had gone, and at first glance there was no 

 evidence of the overlapping chitin that bridges over the 

 girth. A closer look, however, showed the prominence at 

 the base of the under-wing that forms the anterior over- 

 lapping margin, with a linear groove just behind it, and on 

 the middle of the fore-wing at the position of the tunnel for 

 the girth is a glazed line, but no definite overlapping. It 

 therefore seems that the pupa is prepared for the girth tak- 

 ing its pi'oper position by a definite channel occurring across 

 the wings whilst the cuticle is still plastic ; that the two 

 special places (on fore- and hind-wing) are prepared for 

 its inclusion beneath the surface; that of the hind-wing 

 which is a very strong lappet forms even if the girth is not 

 there ; that on the fore-wing, the overlying lappet does 

 not form, unless it has the assistance of the downward 

 growth of the wings, which occurs during the maturing of 

 the pupa just before hardening, and as the lappet is not 

 formed, the walls of the tunnel that would contain the 

 girth are left exposed as a glazed line in this position. 



As a subsidiary effect of cutting the girth the pupa did 

 not succeed in fastening the cremnster on the provided 

 anal pad of silk. When at rest for pupation the claspers 

 hold the silk in front of the pad, which stands up un- 

 occupied just behind the pupa, or rather behind the 

 claspers and under the end of the anal plate, and in 



