140 INSECT TRANSFORMATION 



have pupae with the appendages and wings less closely adherent 

 than those of the more specialized Lepidoptera ; such pupae 

 are often defined as " incompletely obtect ' or incomplete. 

 While an obtect lepidopterous pupa has usually only two 

 or three abdominal intersegmental junctions with flexible 

 cuticle, so as to allow freedom of movement between very 

 few abdominal segments, an " incomplete ' pupa (Fig. 80) 

 may have four or five segments capable of movement. 1 The 

 abdominal segments in an " incomplete ' pupa are often 

 provided with rows of spines, which are not present on an 

 obtect pupa. This difference is correlated with a divergence 

 in behaviour, for the spines are serviceable to the former in 

 facilitating its partial emergence from the cocoon in preparation 



FIG. 8l. PUPA OF FEMALE SNAKE-FLY (Raphidia), SIDE VIEW. 



op, ovipositor, x 3. 



for the final moult and the liberation of the imago, while the 

 latter, which has no spines, remains enclosed in its cocoon or 

 attached to its suspensory pad, so that all necessary locomotion 

 must be performed by the winged adult after the final moult. 

 Such differences among pupae as regards activity and power 

 of locomotion are often associated with peculiar modes of life 

 as well as with characteristic structural features. It may 

 suffice to mention the case of the curious snake-flies (Raphidia), 

 of which the pupa (Fig. 81) is easily recognized as it presents 

 the distinctive narrow, elongate head and prothorax of the 

 imago. For the greater part of its life as a pupa it remains 

 at rest in a cavity of the wood which served the larva as a 

 hunting ground, but as the time for the final moult draws 

 near it leaves its shelter and runs about actively. 



1 T. A. Chapman : " Structure of Pupae of Heterocerous Lepidoptera ". 

 Trans. Entom. Soc. t Land. 1893. 



