152 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



female abdomen shows that the number of eggs laid by a single 

 female is about forty. 



The mine, (figs. 38-39), begins as a narrow line which runs out 

 towards the edge of the leaf. This early part of the mine is nor- 

 mally obliterated and makes a fissure in the leaf as this grows. 

 This fissure is a very characteristic feature of infested leaves. 

 After this short linear part the mine broadens out into a large 

 bulgy blotch, which always runs out to the edge of the leaf, and 

 normally involves the tip or one or more of the lobes. The mine 

 is suggestive of a beetle or a sawfly mine. The entire parenchyma 

 of the leaf is eaten out and the mine is equally visible from both 

 sides of the leaf. It is semi-transparent, so as to show plainly 

 the larva and the black frass, which is voided in long, irregularly 

 curled threads, lying loosely within the mine. 



The full grown larva (fig. 1), is 9-10 mm. long, apodal, whitish 

 in color, somewhat flattened. Head small, flat, horizontal, light 

 yellow with dark brown trophi. Thoracic segments large and 

 bulging, first segment with lightly chitinized but rather strongly 

 pigmented, dark brown thoracic shield and sternal plate. Abdom- 

 inal segments evenly tapering to the last joint. The skin is sha- 

 greened, due to numerous minute, closely set, spine-like projec- 

 tions (fig. 3), all directed backward and probably used in the 

 locomotion. One pair of thoracic and eight pairs of abdominal 

 spiracles. 



In the head (figs. 6-7), the two halves of the epicranium are 

 dorsally strongly prolonged backwards, separated by the very 

 deep upper portion of the occipital foramen; ventrally also they 

 are prolonged backwards, but only half as far as on the upper 

 side. Ventrally on the inner margin of each side of the epicran- 

 ium is a large triangular piece, the hypostoma, 1 which supports 

 the transverse bridge-shaped part of the tentorium. 



On the upper side of the epicranium is found one long anterior 

 seta, three minute setae and several sensorial punctures, some- 

 what asymmetrically arranged. On the under side are found one 

 large and five small seta?. No true ocelli, but only a large, strongly 

 pigmented, ventral eyespot on each side near the antennal base. 



The front 2 is nearly triangular, but the converging edges do not 

 quite meet posteriorly at the occipital foramen. These edges are 

 strongly chitinized and interiorly developed into the endoskeletal 

 frontal ridges. The front contains two pairs of sensorial punc- 

 tures but bears no setae. 



1 This is probably the post-gena of Kellogg. Kansas Univ. Quarterly, vol. 

 n, p. 53, 1894. 



2 We employ this term which was first used by Lyonet, (Traite anatomiquc 

 de la chenille qui ronge le bois de saule, p. 34, 1762), and which has been 

 adopted by \Vm. T. T. Forbes, (A Structural Study of Some Caterpillars, 

 Ann. Ent. Soc. America, vol. in, p. 96, 1910). 



