Eighth Report of the State Entomologist. ]35 



The Caterpillar. 

 The fuli-grown caterpillar measures less than a quarter of an inch in 

 length —more exactly, from 0.18 to 0,22 of an inch. It is of a slender 

 form, tapering considerably at each extremity, and with deep incisures 

 between the rounded segments. The head is long, projecting, slightly 

 bilobed, of a pale brown color, with the ocelli 

 and mandibles black; width of head about half 

 that of the first segment, and one-fourth or less, 

 of the central segments. The body is dull pale 

 green, sometimes of a yellowish cast, having 

 short hairs on the setiferous spots, and some 

 longer ones elsewhere, particularly at the ex- Fioj-Catenjuiar^of the w^^^ 

 tremities, as shown at c in Figure 2, but omitted tmx canadensisella, side 



' . . vie^ and dorsal view (orlg- 



by the engraver in Figure 3. The terminal pair inai.) 



of prolegs are projected behind: the other prolegs are so short that 



the apodal segments also have the appearance of being employed for 



locomotion. 



The caterpillar walks slowly, and when disturbed, drops from the 

 leaf and hangs suspended by its thread. If brushed from the leaf to 

 the table or a smooth surface, it twists vigoroush^ about, in violent 

 contortions, as if to frighten away, or to escape from, its enemies. 



Its Molting Cocoon. 

 In addition to the two New York localities mentioned, the insect 

 is also known to occur in Alban}'. After its reception from Ausable 

 Forks, in Essex county, the birches in Washington Park were examined 

 for it. Leaves eaten after the peculiar manner of the larva', to a 

 moderate extent, were found, but none of the ribbed cocoons. On a 

 number of the leaves were small rounded silken patches, which were 

 identified as the retreats made by the larv;v during their molting 

 periods — apparently in two sizes. They had been described by Dr- 

 Packard, in the 5th Report of the U. S. Entomological v ommission, as 

 " Orbicular, 2 to 3 mm. in diameter, of white silk, inclosing the larva 

 curled up within," and referred to an " unknown Tineid." Different 

 names have been giv* n to these intei'esting objects by recent writers, as 

 cocoonets, cocoons, and pseudo-cocoons. They are, strictly speaking, 

 cocoons, but as it might be confusing to refer to them by this name, 

 any misapprehension would be prevented by calling them " molting 

 cocoons," as suggested by Mr. Brunn in the first description of the 

 structure. Their manner of construction, entrance into them, and 

 occupancy will probably be found to agree with that of the larva of 

 Eucculatrix pomifoliella, minutely given by Mr. A. E. Brunn, in the 

 Second Report of the Department of Entomology of the Cornell 



