40 I July. 



the trail of Lyccena semiargus, L. Corydon, Apatura Iris, Melanargia Oalathea, and 

 many others, which were formerly taken in several localities in the Midlands. — 

 W. Harcouut Bath, Ladywood, Biriningliam : June, 1887. 



[Our correspondent should define more clearly what he intends by " a few 

 years ago." — Eds.] 



The injluence of small birds in assisting the extinction of Aporia cratagi. — In 

 the last No. of the Magazine, the Rev. J. Hellins says that " the protection of 

 ' small birds ' must have some influence " in diminishing the chances of the survival 

 of a large day-flying insect. 



I have collected in Kent for at least Lliirty j'cars, and it must be quite twenty- 

 five years since I last saw Aporia cratagi flying in that county ; but, during the 

 whole of the thirty years, I have never seen any bird but a sparrow attempt to catch 

 a butterfly. In the second place, if it be argued that the larva would be devoured, 

 I can only say that I never knew a small bird to eat a large caterpillar, if it could 

 get one that could be more easily swallowed ; of our indigenous species the robin 

 and the great tit certainly select green caterpillars in preference to others, and, when 

 feeding their young, I have watched both these birds with their mouths full of 

 the green pests of the gooseberry and currant ; from observation of cage birds I 

 should say that the finches certainly show a similar preference, the green larvffi of 

 Mamestra being chosen before the brown, though all are greedily devoured. 



However, apart from these facts, my experience is that the "Wild Birds Pro- 

 tection Act " has not prevented the rapid decrease of many of the small birds in 

 Kent ; the wholesale destruction of woods, combined with active building operations, 

 are more than sufllcicnt to render such an Act a mere farce, so far as finches and 

 warblers are concerned. It is true that blackbirds, thrushes and skylarks, which 

 might eat the larva? of A. cratcegi, liave all increased of late years ; but the Act 

 does not protect these birds. — Akthdr G. Butlee, 10, Avington Grove, Penge : 

 April 30th, 1887. 



Odour observable in males of Pieris napi. — I am able to confirm in the most 

 positive manner the observation recorded by Mr. R. C. L. Perkins, ante, p. 11. I 

 have been aware of the existence of this odour since 1829, and I published the 

 following note on the subject in the " Mcmoires de la Societe Eoyale des Sciences de 

 Li<?ge," tome 2, 1841., in my " Enumeration des Lepidopt^res de la Belgique :"— 

 " This is the place to remark that the $ of Pieris napi has a very strong aromatic 

 odour, similar to that of thyme. I am surprised that no entomologist has noticed 

 the existence of this odour, which is constant. I think that the £ of the var. 

 bri/oni<B, from the Simplon, has the same odour." 



Now, in 1887, I am able to complete my old note of 1844, by saying that I have 

 since taken in other parts of the Swiss Alps (where the $ napi type is always 

 replaced by the var. $ brgonice) males giving out the same odour as the ordinary 

 males of Belgium, &c. I likened this odour to that of thyme, but Mr. Perkins' 

 comparison with that of verbena is more exact. It is to be desired that some 

 biological chemist will study the cause of this odour, which exists always in the J 

 of P. napi and its varieties, but never in the ^ . 



My note, translated above, was given when characterizing the variety nigro- 



