NOTES, CAPTURES, ETC. 23 



familiarly, there is not a pin to choose between the hairs of P. 

 clirysorrlicea and those of P. simUis, only from the occurrence of 

 the former species in colonies we are more likely to perceive the 

 disagreeable influence of their protective coating. The theory 

 has been put forward (has it not ?) that from the scarlet cup-like 

 spot on the tenth segment of the larva a fluid is ejected which 

 irritates, as in the case of Dicranula vinula, but I do not think 

 this has been confirmed by dissection. It is amply proved that 

 the cocoons cause irritation, as also the moths, concerning which 

 Mr. Anderson's suggestion is a plausible one. The oddest cir- 

 cumstance is that the hairs of the larvae seem to set up this 

 irritation, not by puncturing the skin, but by simply lying upon 

 it ; of course the irritation once started, is generally increased by 

 rubbing. Perhaps we may suppose that the hairs are beset with 

 numerous fine particles, and these, falling off, are taken up by the 

 j)ores of the skin. A lotion of arnica, applied cold, will probably 

 be found the best remedy. It may be added that a similar effect 

 has been experienced from the hairs of the larvse of Arctia caia 

 and A. villica. — J. R. S. Cliffoed ; Cambrian Grove, Gravesend. 

 —December 11, 1884. 



Exchanging. — Few of us can hope to form anything like a 

 complete collection of British insects unless we have unlimited 

 time and means at our disposal. Hence the necessity for your 

 Exchange List, which is quite the recognised medium between 

 collectors. The system under which exchanges are effected, 

 among advanced collectors at any rate, is that of " marked lists." 

 Now it is about these that I have a word to say. Does it not 

 stand to reason, that when a collector has obtained full series of 

 more than half the British species, the shortest method, both for 

 himself and his correspondent, will be to place a mark against 

 those species only which he wants ? Instead of this, my expe- 

 rience is that if a friend wants, say two species out of a hundred, 

 he will put his mark against ninety-eight and leave the two blank. 

 Let such a person consider the waste of time thus caused to both 

 contracting parties, and mend his ways. If any one knows the 

 value of time, surely it should be an entomologist. To the four 

 virtues required of us in the pursuit of any science — patience, 

 energy, observation, and accuracy — may surely be added a fifth, 

 appreciation of the value of time. In the good old days, when 

 "exchanging" specimens first began, it was com^jaratively 



