26 



the family Eriocraniidac and shown in part in Figure i, mp. They 

 may also be seen in Figures 28, 30, 32, 36, 38 ; mp. Structures which 

 may be maxillary palpi are found in the genus Gracilaria (Fig. 47). 

 The peculiar extensions of the maxillae in the Cossoidea and Eu- 

 cleoidea are not considered as maxillary palpi (Figs. 15, 19, 23). 



THE THORAX 



The three segments of the thorax are always distinct. They are 

 only visible on the dorsum, because the ventral and lateral surfaces 

 are covered by the appendages. 



Prothorax. — This segment probably varies more in size and shape 

 than any of the others. There are some forms, as in the Gracilarioi- 

 dea, Yponomeutoidea, and others, where the prothorax is very short 

 on the meson (Figs. 53, 56, 58; p) or even invisible (Fig. 54), but is 

 very wide at each lateral margin. It is longer in the Galleridae and 

 certain families of Noctuoidea than in any other pupae examined. 



Prothoracic Legs. — These lie adjacent to the maxillae at their 

 proximal end. The coxae are frequently exposed, especially in gen- 

 eralized pupae where the appendages are free (Figs. 1, 11, 19; cxi), 

 and dissection frequently showed a segment cephalad of the coxa, 

 the trochantin, although there was no distinct suture indicated on the 

 exterior, this being covered by the mouth-parts. The trochanter is a 

 very small segment usually found at the caudal end of the femur 

 when the leg is folded and is therefore generally concealed by the 

 tibia and tarsus. The femur extends from the trochanter cephalad to 

 the caudal margin of the head. It is frequently concealed by the tibia 

 and tarsus which are the only portions of the prothoracic leg always 

 visible, but they are often shoved slightly laterad so that a portion of 

 the femur is exposed (Figs. 1, 8, 24, 32, 36; fi). The tibia and tarsus 

 are seldom divided by a suture except in generalized pupae, where all 

 the segments, even of the tarsi, are readily distinguished (Fig. 1, l x ). 



Mesothorax. — The mesothorax is usually considerably longer than 

 the other segments in specialized forms, but in generalized pupae all 

 the segments are more nearly equal. 



Mesothoracic Spiracle. — This is usually located on the dorsum be- 

 tween the prothorax and mesothorax, sunk deep in the conjunctiva 

 between the segments with an opening adjacent to the caudo-lateral 

 angles of the prothorax. Its primitive position appears to have been 

 much farther ventrad (Fig. 2, msp) and it is found in this position 

 in the specialized Trichoptera. It retains this primitive position in 

 the superfamily Eucleoidea and in the family Nepticulidae. The 

 caudal margin possesses curious modifications in different families in 



