LIFE-HISTORY OF CHARAGIA VIRESCENS. 33 



it is tolerably uniform in thickness throughout, and of a dull 

 yellow colour. The head is large, dark chestnut-brown, very 

 irregularly striated, and covered with a few short yellow bristles. 

 The prothoracic segment is hard and shining, with the back and 

 sides ruddy brown, the ventral surface being dull yellow ; its 

 spiracle, which is very large, is situated near the posterior 

 margin, and a little above it there is a dull black spot, filling a 

 slight concavity about the same size as the spiracle itself. The 

 second and third thoracic divisions are without breathing orifices, 

 all the rest of the segments, except the last, being provided with 

 a pair situated in the connecting membrane between them. 

 Each of these has on its dorsal surface two corneous plates of an 

 oblong form with rounded angles, the larger of which is situated 

 on the anterior portion of the segment, except on the second 

 thoracic, where the arrangement is reversed, the smaller one 

 being in front of the other. These plates are all divided into 

 two portions by a dorsal line of soft membrane which runs down 

 the middle of the larva. On the sides of the two posterior 

 thoracic segments there are several small plates of irregular 

 shape resembling those on the back ; on each of the abdominal 

 segments there are also two plates of an oval form situated just 

 below the spiracles, and lying one above the other ; these are all 

 bright ochre in colour, hard, and shining. The anal segment is 

 entirely corneous, and dull brownish yellow in colour. Prolegs 

 are situated on the third, fourth, fifth, and sixth divisions of the 

 abdomen ; they are of a dull yellow hue, and are furnished with 

 a row of very fine black hooks round the edges of that portion 

 applied to the ground. Anal prolegs darker. The whole insect 

 is sparingly covered with isolated yellow and black bristles. In 

 many larvae the ventral surface and connecting membrane be- 

 tween the horny pieces is light purple. Younger specimens 

 principally differ in being of an olive-green colour, which is con- 

 siderably darker when they are very small. 



The last act performed by the caterpillar previous to under- 

 going its transformation is the construction of the trap-door at 

 the top of its burrow ; this done the insect retreats to the bottom, 

 its last segment resting on the termination of the vertical 

 gallery; after this it becomes torpid and stiff, then violently 

 wriggles, and the skin, splitting open on the thorax, is worked 



ENTOM— FEB., 1885. F 



