May, 1914.] The Cheese Skipper. 311 



segments. Except for its slendemess 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 S 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 Sth 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 .026 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 sclerites (m. s.). These 

 articulate posteriorly with the hypostomal sclerite (h. s.). 

 The hypostomal sderite consists of two irregular lateral bars 

 united by two ventral bars of chitin. 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. 



