May, 1914.] 
The Cheese Skipper. 
3 11 
segments. Except for its slenderness and smaller size, the cephalo- 
pharyngeal skeleton is similar to that in the adult larva. The 
tracheal trunks open to the exterior through two anterior and two 
posterior spiracles, similar in structure and position to those of 
the mature larva. On the caudal segment are found the two 
posterior, two dorsal, and the paired angular lateral projections 
present in the adult. The paired angular lateral projections are 
not so promiinent as in the mature larva. 
The full grown larva (Fig. 7) measures 9 to 10 mm. in length, 
and about 1 mm. in width (5 live specimens). Preserved specimens 
measure 8 to 9 mm. in length, 1.17 mm. in width, and .9 to 1.17 
mm. in height. General shape of larva is cylindrical; truncate 
at posterior end; tapering gradually to a bilobed, narrower an¬ 
terior end. Widest portion in the region of the 7th and 8th seg¬ 
ments. To the unaided eye the general color is white to yellowish 
white; under the binocular yellowish-white to brown, especially 
in the regions posterior to the 4th segment. The tracheal trunks, 
the black chitinous mouth parts, and viscera are visible through 
the integument. Except for the three irregular transverse rows 
of spines already mentioned, the integument is smooth. The body 
of the larva is divided into thirteen segments. 
The bilobed cephalic or pseudocephalic segment is .15 mm. wide. 
The antennal tubercle (Fig. 13) located on the antero-dorsal sur¬ 
face of each of the oral lobes consists of three segments and meas¬ 
ures .02(3 mm. long by .017 mm. wide at its base. The cephalo- 
pharyngeal skeleton (Fig. 14), visible through the integument, ex¬ 
tends from the ventral middle portion of the pseudo-cephalic 
segment to the posterior part of the second segment. It con¬ 
sists of two uncinate mandibular sclcrites (m. s.). These 
articulate posteriorly with the hypostomal sclerite (h. s.). 
The hypostomal sclerite consists of two irregular lateral bars, 
united by two ventral bars of chi tin. Posteriorly the hypostomal 
sclerite articulates with two processes on the anterior edge of 
the lateral pharyngeal sclerites (1. p.). Each of the lateral 
pharyngeal sclerites are wider posteriorly than anteriorly, and 
the posterior is deeply incised. They are united dorsally at the 
anterior end by a dorsal sclerite (d. p. s.) and ventrally "they are 
continuous with the floor of the pharynx. 
The caudal end of the larva (Fig. 8) measures .77 mm. wide and 
.71 mm. high (preserved specimens). On the posterior surface of 
the last segment and ventral to the caudal spiracles are located 
two fleshy tubercles .17 mm. apart (p. t.); each tubercle measures 
.13 to .17 mm. long and .068 wide at base. On the dorsal 
surface of each spiracular lobe is a fleshy tubercle (d. t.) measuring 
.05 mm. in length by .025 mm. in width. On the lateral 
surfaces of the last segment are located paired angular-like pro¬ 
jections, (1. an.) measuring about .05 mm. long by .068 to .085 mm. 
wide at the base. 
