BY EL J. TILLYARD. 641 



cubito-niedian and distal Y-veins respectively. Neither of these 

 veins is preceded by a trachea in the freshly-turned pupa. Other 

 points to be noted are: — • 



(1) The composite origin of R, which is particularly notice- 

 able in the forewing. 



(2) The composite origin of M ('See Plate xxxii., fig. 17) . 



(3) The fact that Cu2 is already reduced in the forewing. 



(4) The very distinct origin of the anal group of trachea?, 

 in a single bunch far removed from Cu, with all three anal 

 tracheae clearly indicated. 



(5) The fusion of 1A with Cu2 in the bindwing, for a short 

 distance near the base. This latter character is claimed by 

 Comstock to be peculiar to the Trichoptera; but, as it also oc- 

 curs in the Jugo-frenata, it is used as part of the argument for 

 removing those insects to the Trichoptera (15) . 



(6) The complete separation of the three anal veins in the 

 forewing, except at their bases. 



Pupa? dissected at ages from a few days to more than a week 

 old show little difference from the above. The wing becomes 

 generally more opaque, leaving the paler and more transparent 

 bands, along which the imaginal venation is later laid down, 

 clearly visible. No trachea was seen by me along the course of 

 M 5 in any pupa of this age, nor did 1 ever succeed in finding 

 a trachea along the course of M 4 in any pupa of any age what- 

 ever. 



In the older pupa?, the wing becomes darkened; and, with a 

 little care, it may be removed whole from its sheath, without 

 damage. The base becomes narrowed, so that the condition of 

 the basal tracheation is completely altered. The formation of 

 scales becomes very apparent, and greatly hinders the study of 

 the trachea? in situ. In order to make out the courses of the 

 trachea? near the base, I cleared some of the wings very rapidly 

 in chloro-phenol*. There is usually only just time to see the 

 condition of the trachea? plainly, when this strong clearing agent 

 is used; for the trachea? are no sooner cleared than they begin 

 to shrivel up, so that drawings must be made at once. 



In a pupa which was evidently only a few days from meta- 

 morphosis, seeing that the colouration of the wings was beginning 



*I have to thank Dr. H. Priestley, Lecturer in Physiology, University 

 of Syrlney, for l>ringing this strong clearing agent to my notice. 



