572. , Dr. Thomas Algernon Chapman on the 



it really is that emerges, but does so encased in the 

 pupal skin. To achieve this object, it seems to have 

 been found most efficient to have three, four, or five 

 abdominal segments capable of movement, but to have 

 the terminal sections soldered together. So few as two 

 free segments is found only in the Grac'dariiclfe, and is, 

 therefore, probably a number disadvantageously small. 



A cremaster is very rare in this section, and its use, 

 where it exists, appears to be to enable a cable of silk not 

 to retain the pupa within the cocoon, but to restrain it at 

 precisely that degree of emergence from the cocoon that 

 is most desirable; this is usually attained when the 

 movable segments have so far emerged from the cocoon 

 that they are no longer capable of acting in the cocoon 

 as locomotor organs. The pupa usually retains tliis 

 position by the elasticity of the cocoon gripping it tightly, 

 but in many To^'trices and others a cremaster and loose 

 cable as just mentioned exists. 



The next step, that intermediate between the Incom- 

 'pleiie and Ob!ectw, 1 have so far only met with in the 

 genus Epermenia (CliauUodus). It probably results in 

 some instances from a cremaster preventing the escape of 

 the pupa from the cocoon, and a slender cocoon permitting 

 the escape of the moth. 



We want many more facts at this point, if perchance 

 they are attainable. The transition is a very notable one, 

 we pass from what we might almost call the true lepi- 

 dopterous (if it were not also equally dipterous) process 

 of emergence, emergence within the pupal skin, to the 

 direct emergence of the imago from the cocoon, leaving 

 the pup'ril skin behind it, precisely the process in the 

 bees and beetles, with the important difference that 

 imaginal jaws are not required, and the less important 

 one that some final expansion and hardening have still 

 to be accomplished. 



It puzzled me a great deal to understand why the 

 Ohtecim always had the fifth and sixth abdominal segments 

 free and no others, both sexes being the same. The 

 exceptions being almost literally none, and Epermenia 

 being, so far, the only transitional form I had met with. 



Now throughout the Ohtectfe there are many devices 

 for breaking through the cocoon : specially constructed 

 weak places in the cocoon, special softening fluid, applied 

 by the moth, assisted by special appliances of diverse 



