REPLY OF JANUARY 11 TIT, 1858. 15 



Mr. Logan is a very good entomologist and one imbued with the 

 right scientific spirit. I am glad he has written to you. 



Your insect is no doubt a Lithocollctis and possibly one already 

 named Acaciella, but on this point I can speak more decidedly 

 when I see your specimens. 



You Avill have noticed lately in the " Intelligencer" I have 

 introduced one or two paragraphs referring to American Micro- 

 Lepidoptera ; if you can meet with any of the species to which 

 I have alluded I should be very glad of specimeus. 



The pins No. 19 and 20 are almost identical, but No. 19 is 

 perhaps a trifle the more slender ; either of them should do for a 

 Lithocolletis ; one collector here uses even No. 19 for Nepticulce! 



The eggs of the autumn brood of your insect are probably 

 deposited on the young bud of the Robinia, but some autumnal 

 species appear to hybernate and perhaps deposit their eggs in 

 spring. 



All the Lithocolletides of which the neuration has been inves- 

 tigated agree with the figure of Messaniella in the " Ins. Brit." 



Your three laws approximate to the truth without attaining it. 



1°. In any given species you may meet with individuals of 

 aberrant neuration : a kind of deformities — but such examples are 

 naturally very rare. 



2°. You will sometimes meet with minor modifications in different 

 species of the same genus, with no apparent modification or differ- 

 ence of habits. 



3°. That neuration often gives us positive characters when all 

 else appears hazy and indistinct is a great convenience — we per- 

 haps suspect a difference, and the investigation of the wings con- 

 firms our suspicions. 



I return your sketches (of which I have had a copy made), with 

 many thanks for the sight of them ; I see in the anterior wing 

 you have committed the error of turning it the wrong way up. 

 In the enclosed sketch I have marked in pencil the veins which 

 I fancy you may have overlooked, and hence caused the discre- 

 pancy of which you complain. 



Dipterous larvae deposit their excrement at considerable in- 

 tervals ; it never forms the same continuous track that it does in 

 the mines of Lepidopterous larvae : for distinguishing Coleopterous 

 mining larvae there is nothing for it but experience, — I am myself 

 often mistaken. Sometimes I neglect Lepidopterous larvae, fancy- 

 ing them Coleopterous ; at other times I collect Coleopterous 

 larvae, thinking them Lepidopterous. 



Excuse my letter not being so long as yours, for the length of 

 which I am sure no apology was necessary, as it contained so much 

 matter of extreme interest to me. 



I enclose you a letter from Dr. Herrich-Schaffer of Ratisbon, one 

 of the most energetic and voluminous entomological writers in 

 Germany. 



