August 1S91.J 



PSYCHE. 



123 



inner margin lateritious. Pupil of the 

 ocellus pale, with a central white dash. 

 Length from tip to tip of the expanded 

 wings z\ inches. Female fuscous ; 

 upper wings with the lines & maculae 

 dark & somewhat hoary ; under wings 

 croceous, with the same concentric arcs 

 & pupil as the male. Length between 

 the wing 3* inches. The larva of this 

 Bombyx is particularly curious — it is 

 between 2 & 3 inches long, & covered 

 with greenish or light yellow spines 

 which, like those of the nettle are per- 

 forated, stinghig, & contain a poison- 

 ous I iquor. The chrysalis hybernates 

 in a thin, silky, firm, cocoon ; & the 

 perfect insect is developed about the 

 middle of June. It may, perhaps, be 

 well known to you ; if so, what do 

 you call it ? 



In the Edinburgh Encyclopaedia I 

 find many genera, of the order Lepidop- 

 tera, accredited to Fabricius, which do 

 not appear in his Entomologia System- 

 atica, printed in 1 793 ; nor do I know 

 in what work of Fabricius these genera 

 are to be found. This makes it ex- 

 tremely difficult to study the order 

 Lepidopt. and almost impossible for a 

 novice to ascertain the species which 

 belong to the modern genera. Is Co- 

 quebert's Decade a very valuable book 

 to the student, and can you inform me 

 its cost & probable utility? 



I should like much to see Mr. Worth's 

 paper, when published. 



If I do not intrude on your time & 

 patience, I hope you will allow me, 

 occasionally, to address you ; & in 

 return, to favour me with your replies. 



In this way you will, from the centre of 

 science in which you preside, shed light 

 on an obscure individual, groping his 

 way without access to books, & un- 

 aided by instruction, but anxious for 

 information, & desirous to obtain it 

 from the best sources. 



Be pleased to receive my congratula- 

 tions on your safe return from your late 

 expedition, & my hopes that it will be 

 productive, to yourself, both of honour & 

 reward . 



I am, Sir, with great respect, 



Your humble s erv't 



T. Wm. Harris. 



P. S. May I not hope to hear from 

 you soon ? 



[DRAFT OF REPLY BY THOMAS SAY.] 



Dear Sir — 



I avail myself of a leisure interval to 

 reply to your letter of the 22nd ult. I 

 was not aware that an yEgeria inhab- 

 ited the Cherry tree, but of the fact 

 there can be no doubt as you found the 

 larva in the trunk and limbs of the tree. 

 Your desc'n of this insect and that of 

 the specimen from the peach tree, 

 agree perfectly with those I have dese'd 

 as the sexes of AL. exitiosa. That my 

 two specimens are male & female I 

 have no doubt, hut that they are sexes 

 of the same species I hold Mr. Worth 

 responsible ; they do indeed differ very 

 much in appearance, but so also do 

 other sexes of identical species of the 

 same genus. The anus of yEgeria is 

 far more obviously bearded than that of 

 Zygaena many of which latter are 



