578 



Dr. D. Keilin on the 



Each egg is surround eel by a gelatinous layer, and they are 

 all embedded in a coranion gelatinous mass, somewhat 

 similar to that of various Cliironomids or Rhyphids (R/u/phus 

 and Mycetohia). The egg is of a very dark brown colour 

 and of a peculiar shape, which to my knowledge has not 

 yet been encountered in any otlier insect. It is of elongate 

 oval shape, 500 /z lono- and 75 yu. in diameter, and sharply 

 bent in its middle so that its two branches come almost into 

 contact. The embi'yo and the young larva have tlie same 

 curvature as the egg. When the larva hatches, the egg is 

 split at one end, corresponding to the anterior and dorsal 

 side of the enclosed larva, and the two edges of the split 

 roll up externally, leaving a triangular opening througli 

 which the larva escapes. 



Text-fi<^. 1. 



A small portion of an egg-mass o^ Dasyhelea obscura, slaowing the eggs 

 (rt) before and {b) after the hatching of the larvae ; the gelatinous 

 mass covering the eggs is not represented in the figure. 



III. Larva. 



The larva when it hatches from the egg is 0'7 mm. long; 

 it grows, undergoing several moults,' and Avhen ready to 

 pupate it reaches 4 to 5 mm. in length and 0-2 to O'S mm. 

 in diameter. The movements of the larva are very slow; 

 it does not swim, and, when immersed in water, it crawls very 

 slowly on the bottom of the dish, bending and unbending 

 its body. The latter is comj)Osed of a head, 3 thoracic and 

 8 abdominal segments, the last abdominal segment being 

 double(Pl. XIX. fig, 8). 



