s^^Mfsm^ 



Eighth Report of the State Entomologist. 135 



The Caterpillar. 

 The full-grown caterpillar measures less than a quart* r 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 tiie first segment, and one-fourth or less, 

 of the central segments. The body is dull pale 

 u, sometimes of a yellowish cast, having 

 Short hairs on the setiferous spots, and some 

 longer ones elsewhere, particularly at the ex- Fig. 3-Caterpiiiar of thebirch- 



° ■ • leaf Bucculatnx, Bucct^a- 



tremities, as shown at c in Figure 2, but omitted trix cavadkn-sisklla side 



° ' vie x an1 dorsal view (orig- 



by the engraver in Figure o. The terminal pair iaai.) 



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 vigorously about, in violent 

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



Its Molting Cocoon. 

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

 is also known to occur in Albany. 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 1 , 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 larva' during their molting 

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

 Packard, in the 5th Report of the U. S. Entomological ^ 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 interesting 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 w^ould 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 

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

 Second Report of the Department of Entomology of the Cornell 



