56 XYLOPHASIA LITHOXYLEA. 



They are cylindrical, and tapering a little from the 

 third segment to the head, and again from the eleventh 

 to the anal extremity ; the third and fourth segments 

 subdivided by transverse wrinkles, the others plump, 

 well defined, and puckered a little along the sides ; the 

 usual dots in both species assume the character of 

 tubercular warts, each furnished with a hair. Like the 

 head and plates they are black or blackish-brown in 

 colour, and in shape and arrangement are found as 

 follows : the central transverse series on the back of 

 the third and fourth segments are oblong, and are pre- 

 ceded and followed by a fusiform transverse spot, dor- 

 sally divided by a thin line of the ground colour, which 

 is also seen to divide the anterior plate, while on the 

 sides of these two segments are grouped several more 

 or less roundish spots. On the back of each of the 

 other segments (save the last) are four large black 

 spots, the trapezoidals ; these have the first pairs 

 round, the second pairs roundish-ovate. Along the 

 sides of each of these segments are grouped five spots 

 in this way ; the spiracle is surrounded by four of them, 

 viz. a large one above and below, one behind much 

 smaller, and the smallest, a mere dot, in front ; the 

 fifth spot is the lowest, and where the ventral prolegs 

 occur is borne on them; the thirteenth segment has 

 spots in front and a plate behind ; the ventral and 

 anal prolegs are broadly barred near their tips, which 

 are fringed with hooks of the same colour as the head 

 and plates. 



Lithoxylea, full grown, is about an inch and a half 

 in length, and stout in proportion ; its brownish-grey 

 ground colour has a slight fawn tinge in it, and is but 

 little paler below the spiracular region, though the belly 

 has a faint tinge of greenish. The pulsating dorsal 

 vessel is of a deeper tint than the back ; the upper lip 

 darkish fawn-colour, the antennal papillae a little paler ; 

 the anterior legs fawn-colour, and often tipped with 

 blackish ; spiracles black. 



Polyodon, when full grown, varies in length from 



