100 THE ENTOMOLOGIST. 



heard it suggested that the green nucleus is the acorn atro- 

 phied, the scabrous and setaceous envelopes the cup con- 

 siderably metamorphosed. — E. Newman. This form of gall is 

 called the artichoke gall, and is produced by Cynips Fecun- 

 dalrix of Harlig. I have not been able to rear the fly ; I 

 believe it changes in the earth. — Francis Walker.'^ 



44. Acari on the JVimjs of Trip keen a pronitba. — I took a 

 specimen of Triphaena pronuba the other day with no less 

 than fifty-one small red Acari attached to the wings. — Rev. 

 E. Hallett Todd ; Burford, Oxfordfiliire, September 16. 



[These Acari have been very abundant on the wings of 

 insects this year : at a late Meeting of the Entomological 

 Society, Mr. M'Lachlan exhibited specimens on the wings 

 of Libellula striolata, when Professor Westwood remarked 

 that the Acari had probably taken up their position for the 

 purpose of sucking some fluid matter, wliich went to show 

 that the tviiiy-veiits loere not (as had been supposed) mere 

 horny matter not cofituininy Jliiid : Professor Westwood 

 must have known, but had probably forgotten, that Dr. 

 Bowerbank, in the 1st volume of the 'Entomological Maga- 

 zine,' clearly proved that the wing-bones or wing-rays of 

 insects contained delicate blood-vessels, tln-ough which the 

 passage of the blood was plainly discernible inider a micro- 

 scope : since that date, 1832, no one has presun)ed to doubt 

 a fact so clearly demonstrated, — Edward Newman.] 



45. Number of Cha/ujes of Skin in the Smeri/iihi. — I see 

 (Entoui. 67) you propound a query relative to the larva of 

 Suierinthus Populi and the Smerinthi geuerally. 1 have 

 many times reared both S. Populi and S. ocellatus from the 

 egg : they have always, in my experience, undergone three 

 changes of skin. S. ocellatus attains its full size in about 

 forty-five days on the average ; S. Populi I have found of 

 rather slower growth, usually about five days longer. It is a 

 question of some interest, I think, whether the number of the 

 ecdyses is in all cases the same in each species : I am rather 

 inclined to the supposition that it varies in diflf'erent indi- 

 viduals in some species, though I have no exact data to 

 found this upon as yet. The iSuierinthi frequently consume 

 the cast-off skin, except the head. — J. B. S. Clifford; 21, 

 Robert Terrace, Chelsea, September 23, 1864. 



45. Clianges of Skin in the Genus Stnsrinthus. — Having 



