23 



ing the addition of rods on the fifth and sixth abdominal segments 

 corresponding to those on the sides of the third and fourth. The 

 most remarkable variation seen by the writer was a small rod pro- 

 duced on the middle line of the body just anterior to the vasiform 

 orifice. All the wax rods arise from conical bases, and appear to be 

 formed in sections, each section being sub-cylindrical, tapering grad- 

 ually outward and ending in a cone, at the inner end of which is a 

 conical cavity which fits over the outer end of the section directly 

 behind it and nearer the surface of the body. Through the middle 

 of each wax rod runs a narrow cavity. This structure is plainly 

 seen, both directly under a microscope and by dropping a few of the 

 wax rods into a drop of xylol on a glass slide and observing them as 

 they dissolve. 



A little outside of the outer submarginal series of rods, and 

 alternating with them, is a row of minute pores, which vary in num- 

 ber, extending all around except at the caudal end. Sometimes one 

 is absent and sometimes two occur where but one is normally pres- 

 ent. Farther up on the dorsum there are about fifteen or sixteen 

 pairs of similar pores. In general, it may be said that there is a 

 double row of these on each side of the middle of the dorsum. None 

 have been found by the writer on the second or the ninth abdominal 

 segments. Other pores than those included in the above groups may 

 sometimes be seen. Usually near each pore is a glistening point, 

 which may be a minute seta, as it appears very much like the struc- 

 tures found in Aleyrodes fernaldi,* which are, however, many times 

 larger. 



On the venter (Plate III, Fig. 14) the legs, antennae and mouth 

 parts are distinguishable with some difficulty, except in specimens 

 that have recently moulted. The legs and mouth parts are as in the 

 previous in star. The antennas now lie partly hidden in pockets sit- 

 uated, one on each side, just outside of the anterior pair of legs. 

 They are directed backward and are straight, quite thick at the base, 

 gradually tapering toward the tip, where they are abruptly narrowed 

 and end in a short pointed process. Transverse wrinkles may be 

 seen, but there is no distinct segmentation. A pair of spines occurs 

 on the ventral surface, one on each side, below the operculum, as in 

 previous instars. No eyes can be distinguished in freshly moulted 



* Psyche, vol. x, p. 84. 



