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A. T. STANTON— ON THE CHANGES WHICH OCCUR IN 



The form and arrangement of the anterior clypeal hairs and of the posterior 

 clypeal hairs situated on the front of the head (fig. 1 a), and of the palmate hairs 

 situated on the thorax in certain species and on a varying number of the 

 abdominal segments (fig. 1b), are the characters in which the most striking 

 changes occur, and these will now be described in detail. 



Fig. 1. — A. — Head of larva of an Anopheles, dorsal view, showing (a) anterior and (b) posterior 

 clypeal hairs, and (c) frontal hairs, b. — Abdominal segment of full-grown 

 larva of Anopheles albirostris, dorsal view, showing " palmate hairs " fully 

 developed. 



Growth-changes observed in the larva of Anopheles albirostris. 



When newly hatched from the egg, the tiny larva of Anopheles, albirostris is 

 characterised as follows : — The anterior clypeal hairs, the inner being long and 

 the outer short, are simple bristles ; the posterior clypeal hair is also simple and 

 is situated behind and slightly internal to the outer anterior clypeal (fig. 2) ; the 



Fig. 2. — Head and thorax of newly hatched larva of Anopheles albirostris, 

 showing the hairs all simple. 



