The Hunting Wasps 



tint. It should be remarked that this early 

 development of the most delicate organ^ the 

 eye, Is general in all animals. Later, a 

 smoky line appears on the upper part of the 

 groove separating the mesothorax and the 

 metathorax; and, twenty-four hours later, the 

 whole back of the metathorax is black. At 

 the same time, the edge of the prothorax be- 

 comes shaded, a black dot appears in the 

 central and upper part of the metathorax and 

 the mandibles assume a rusty tinge. Gradu- 

 ally a deeper and deeper shade creeps over 

 the two end segments of the thorax and 

 finally reaches the head and the hind-quarters. 

 A day is enough to turn the smoky hue of the 

 head and of the end segments deep black. 

 Thereupon the abdomen begins to share in 

 the rapidly-increasing coloration. The edge 

 of its front segments is tinted saffron; and its 

 hinder segments acquire a dull-black border. 

 Lastly, the antennas and legs, after passing 

 through darker and darker shades, turn 

 black; the lower part of the abdomen is now 

 entirely orange-red and the tip black. The 

 livery is complete except for the tarsi and the 

 mouth-parts, which are a transparent red, 

 and the wing-stumps, which are dull black. 

 io8 



