66i Mr. R. Shelford on the Pterylosis of the 



leathers, at first, are iu two rows, but shortly tliin out 

 to one row only. From this description it will be seen 

 that this tract has now approximated quite closely to 

 the adult condition, a further extension of the outer 

 branch being all that is needed to make them identical. 

 As a result of the great development of the feathers 

 on the throat and neck, it is now no longer possible 

 to distinguish a pteryla colli lateralis : the apterium 

 between that former tract and the pt. spinalis is still 

 apparent, and in fact persists even in the adult, but 

 each half of the tract has now, so to speak, joined hands 

 across the formerly unclothed gap of the throat and 

 become confluent with and indistinguishable from the 

 pt. ventralis. The meagre trichoptiles which in Stages 

 1 and 2 marked the pt. colli lateralis and (incompletely) 

 the pt. ventralis have now totally disappeared. 



Pt. Cauda (fig. 4, p. 661, pt. caud.). — The sheaths of the ten 

 rectrices and their coverts are now prominent : all bear 

 trichoptiles. 



Pt. alaris. — All the feather-sheaths have now pushed through 

 the skin, and in a few cases some of the feathers have 

 just begun to break through their sheaths ; the few 

 trichoptiles that persist are much worn. The arrange- 

 ment of the tract differs so slightly from that described 

 under Stage 2, that I have but few remarks to add. 



Outer aspect. — On the manus there are now five tectrices 

 mediae and five tectrices minores, and one row of 

 tectrices marginales along the pre-axial edge. 



The carpal remex is still much smaller than its 

 covert. 



No new feathers have appeared on the cubitus ; the 

 gap between the tectrices majores and tectrices mediae 

 is as apparent as ever ; the parapteron is now con- 

 tinuous with the former series. There is a bare tri- 

 angular space on the patagial membrane. 



The ala spuria has four feathers with their coverts, 

 continuous, as before, with the covert series of the 

 cubitus. 



