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species, and I find an eighth form different structurally from all 

 the others, but no larger, or rather no longer than the seventh ; 

 and although 1 have not seen the unhatched egg, I have removed 

 larv£e from mines which had not extended to the length of the 

 egg from it, so that I am certain of having seen the first stage. 

 At each moult except the seventh, the length of the larva in 

 its first staoe is added to that of the moultino; larva. Thus L. 

 coryliella Cham, and L. guttifinitella Clem, are each in their first 

 stage 0.56 mm. long. In the second stage they are 1.13 mm., 

 and in their seventh stage 3.95 mm., and in several complete 

 series of specimens now before me 0.56 mm. have been added 

 at each moult. L. ornatella Cham, is at first 0.52 mm. long, 

 and in its seventh stage it is 3.63 mm. long. In L. robiniella 

 and in L. crataegella a somewhat different rule prevails. L. 

 rolmiiella is at first 0,63 mm. lono;, at its second stao'e it is 

 1.26 mm., and so on to the fifth stage, when it is 3.15 mm. 

 long. At its fifth moult there is no increase in size, but its 

 form is changed from moniliform depressed, to a nearly cylindri- 

 cal larva, the trophi have changed from the form given in fig. 2 

 to that given in fig. 4, and the legs are much better developed. 

 In other words, in the cylindrical group a change takes place at 

 the fifth moult, which is equivalent to that which takes place at 

 the seventh moult in the flat and ornatella groups, and which 

 takes place in Phyllocnistis at its last moult before becoming a 

 pupa, which is probably also its seventh. At their sixth moult, 

 however, L. robiniella and similar species add their original 

 length again, and continue to do so at each subsequent moult, 

 including the seventh, at which they pass into the last larval 

 or the prepupal state, thus differing from the larvfe of the flat 

 and ornatella groups, which at this moult do not increase in size, 

 but simply change their forms and structures. In these latter 

 groups the first seven stages are stages of nutrition and growth, 

 not apparently of development ; but the seventh moult and 

 eighth stage are stages of development, and not of growth. In 

 the cylindrical group all the stages are stages of growth and 

 nutrition, except at the fifth moult. The changes which take 

 place at the seventh moult in the flat and ornatella groups, and 

 which continue to progress gradually through the eighth stage 



