NATURAL HISTORY. 9 
serrated, as shewn in the drawing; but whether 
these processes perform the office of teeth, I 
am not certain. The palpi, or feelers, situated 
about the mouth, are flexible, and composed of 
four articulations, as shewn at a; they are very 
transparent, especially about the joints. The 
eyes are disposed in two clusters of six each ; 
in some specimens they are placed at equal 
distances from each other, forming a circle; 
while in others three or four are blended in one 
group, and the rest a little separated. The 
head, when viewed laterally, is flat, and slightly 
tapering, and is so transparent in the infant 
larva, that the palpi are seen through it. It is 
connected with the first segment or prothorax 
by flexible muscles, which allow it to turn 
horizontally or vertically; the latter, however, 
is the most usual motion. In the thorax or 
corselet, composed of the three anterior seg- 
ments, are placed the ganglia, or nervous cords, 
terminated by loops. They are very percep- 
tible in the young larva, as may be seen in 
the drawing, and are of a brighter colour than 
the other parts. The two large vessels, or 
trachez, originating in the head, here attain 
their greatest development, and proceed along 
the succeeding annuli, forming the abdomen, to 
BS 
