LIFE HISTORY OF HYDROUS ( H YDROPHILUS ) TRIANGULARIS. 
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The pupa is snow white throughout when first transformed, but the eyes begin 
to darken in a very short time, and then the various appendages, including the legs 
and wing pads, and finally the body itself, the color assumed being a reddish brown. 
Of a dozen pupse obtained by the present author all were white when taken from the 
pupal chamber except one that transformed within 10 or 15 minutes. Four of them 
remained white on preservation, indicating that they had been formed but a short 
time. The others turned to various shades of reddish brown within 24 hours, the 
depth of shade probably varying with the length of time that had elapsed since pu- 
pation. Two of them became dark brown over the entire surface, approaching 
black in the eyes, the maxillary palps, the tarsi of the legs, and the last two joints of 
the abdomen. In one pupa this color was communicated even to the bases of the 
cerci and the large anterior spines. If the pupa is undisturbed in the darkness of 
the pupal chamber, it probably remains white until the pupa skin begins to separate 
