132 PROC. ENT. SOC. WASH., VOL. 23, NO. 6, JUNE, 1921 



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The second stage larva is amphipneustic. The anterior stigmata are small 

 and are situated just in front of the anterior border of segment III in the 

 middle of the pleural region; each presents two respiratory papillae (Fig. 7); 

 the felt-chamber is uniform in diameter throughout its length. The posterior 

 stigmata (Fig. 8) open on the dorsal aspect of the apex of posterior extremity; 

 each presents two respiratory papillae; the felt-chambers are more robust than 

 in the first stage, the ratio of length to diameter being about 2:1. 



The bucco-pharyngeal armature is represented in figure 9; in this stage there 

 is no median hook, and it is replaced functionally by a pair of elongate curved 

 lateral or mandibular hooks, which are the homologues of the small lateral 

 plates of the first stage larva (Fig. 3); the base of the ventral wing of the basal 

 plate is partly separated from the intermediate region by a short narrow incision 

 but as in the first stage there are no articulations in the armature which forms 

 a solid block. 



The third stage larva (Fig. 10) measures 1 1.0 mm. x 3.0 mm. It is sometimes 

 rather crescentic in form, the dorsal side being slightly concave, the ventral side 

 convex. On the ventral side, the surface of the body presents a series of oval 

 convexities, functioning as pseudopodia and situated in the region of the 

 intersegmental coniunctivae IV-V, V-VI, VI-VII, VII-V1II, VIII-IX, IX-X, 

 X-XI. These pseudopodia are slightly developed on the anterior segments but 

 more prominent posteriorly. The one situated on the conjunctiva X-XI, 

 surrounds the anal opening of the larva. In this stage, the cuticular spines, 

 while perhaps as numerous as in the preceding stage, are relatively much less 

 apparent so that under a low power the cuticle appears to be naked; the spines 

 are arranged for the most part in curving rows separated by rather wide intervals. 

 An anterior band exists on segments I-III, but on segments IV-VIII inclusive 

 this band is broken in the pleural region, while on segments IX-XI, the dorsal 

 part of the band, represented on segment VIII only by a few spines, is absent. 

 The ventral part of the anterior band exists on all the segments to the Xth, 

 where it is interrupted below the pleural region. On segment V there appears a 

 posterior ventral band associated with a posterior pleural group on segments 

 VI-IX. On segment X there is a complete and well developed posterior spine 

 band. The Xlth segment bears dorsal and ventral patches of stigmatic spines 

 as in the preceding stages. 



The third stage larva is amphipneustic; the felt-chamber of the anterior stigma 

 is considerably swollen but diminishes rapidly in diameter distally where it 

 terminates in the respiratory papillae (Fig. 11); these are generally two in num- 

 ber but not infrequently three are present and in some specimens as many as 

 five exist; when such variations occur they are sometimes symmetrical but often 

 not so. The posterior stigmata (Fig. 12) situated on the apex of the posterior 

 extremity, are much larger than in the preceding stages and each possesses 4 

 respiratory slits of which the dorsal and ventral elements are generally short 

 and straight while the intermediate pair are curved; the stigmatic area is 

 surrounded by a well-developed, heavily chitinized, unbroken peritreme; the 

 stigmata in the larva are separated by a distance equal to about one half the 

 diameter of each stigma; the felt-chambers are very short and broad. 



The bucco-pharyngeal armature (Fig. 13) differs greatly in form from that of 

 the preceding stage; the lateral paired mandibular hooks are short, stout and 



