14 



Corresponding spines in different individuals vary slightly in length, 

 but the following figures indicate about the average proportionate 

 lengths. To obtain true lengths in millimeters multiply the figures 

 given by .0035. 



A marginal wax secretion appears soon after the young larva 

 settles down. This arises from minute marginal pores, in the form of 

 narrow ribbons, which unite laterally and form a continuous fringe, 

 the outer edge of which is ragged. This wax is dull, translucent, 

 and contains many opaque brownish granules. The width of the 

 fringe is never more than one-fourth the width of the body. 



The divisions of the thorax are not clearly marked, and it is a 

 question where the head ends and the thorax begins. The abdomen 

 shows eight and possibly nine segments, the last two or three being 

 greatly modified on account of the vasiform orifice. 



This (the vasiform orifice) is about as wide as long, its form 

 being similar to an equilateral triangle with rounded corners (Plate 

 II, Fig. 5.) The entire length from front to rear is about one-tenth 

 the length of the body. The operculum is sub-elliptical in outline, 

 flattened on the basal side. The posterior margin under high power 

 objectives, shows two tooth-like projections — one on each side — be- 

 tween which minute spines can be seen, which appear to extend 

 around on to the under surface of the operculum. The lingula 

 (=lingua) is spatulate in outline, bearing eight longitudinal rows of 

 minute setae above, and two pairs of spines on the caudo-lateral 

 margin, which curve upward and backward. The posterior ones are 

 slightly longer than the others, and are about one-fifth as long as the 

 orifice. The orifice is bounded laterally by chitinous thickenings 

 which do not unite posteriorly. The posterior end of the orifice 

 reaches in this instar nearly to the caudal margin of the body. 

 Just inside the apex of the orifice is a glistening, crescent-shaped 

 structure, whose convex side is directed posteriorly. 



There are two pairs of simple, reddish-brown eyes — a dorsal 

 and a ventral pair — situated nearly opposite each other just mesad 



