THE FOOD-PLANTS OF PHORODESMA SMARAGDARIA, FAB. 197 



The food-plants of Phorodesma smaragdaria, Fab. 



By (Rev.) C. R. N. BURROWS. 



In my paper upon this insect, read at the meeting of the City of 

 London Entomological Society on April 17th, 1900, and published in 

 the Kntn)i)ol(i[iist'ti llrcord, vol. xii., nos. 5, 6, and 7, I made some re- 

 marks and noted some experiments as to the food-plants of the larva, 

 which I acknowledge, with some shame, call for further explanation. 

 I then stated that I did not believe the record of Herr G. Koch that 

 the larva had been found feeding upon Achillea inillefulitan in the town 

 woods of Frankfort-on-the-Main, and further, that when thelarvffihad 

 been twice publicly exhibited in London feeding upon the same plant, I 

 fancied this had been done from motives of policy rather than as a 

 demonstration of fact. I then proceeded to state that I had fed the 

 larva upon (besides its English food-plant, Arteiiiinia niaritima) 

 southernwood and Artcinisia absinthium, while A. vuhjaris (mugwort) 

 was rejected. In a later note [Kntoinolo(iixt's BeennI, vol. xii., no. 7) I 

 recorded some further experiments, the result of which went 

 to prove that Tanacctmn cnhjare (tansy) and Santolina chamoecy- 

 paris.v(s (French lavender) were acceptable foods, while Achillea mille- 

 foliiun, and many more somewhat similar plants, were rejected. It is a 

 remarkable thing that the well-fed larvte, from May 8th under my 

 close observation, actually died rather than finish their growth when 

 confined to Achillea niillefolii(m. It has been said that " wise men 

 sometimes make mistakes, fools never." This is a comfort to me. I 

 was resolved to thresh the matter out, so, when ova hatched on 

 July 5th, 1900, I isolated, in bags out of doors, twelve freshly hatched 

 larva' upon Acliillea iinlleUiliioii, twelve upon Tanacetiim vuh/are, and 

 twelve upon Sa)itnlina. The result was as follows : Of the twelve upon 

 A. iiiillefiiliiiiii, two fed up rapidly, pupated, and produced two males 

 at the beginning of September. The rest hybernated, and, on examining 

 the bag on April 16th, I found nine healthy and active survivors. So 

 much for the food-plant which I found before was not acceptable and 

 incapable of saving the larv* from death by starvation. Of the twelve 

 upon Tanacetiun cnhjaic, I found, on examining the bag, but six 

 survivors, also healthy and active. Of the twelve upon Santolina, 

 I found only dead and shrunken bodies. It is evident that the larvae 

 had fed and lived until hyl)ernation, for they had grown, and, further, 

 spun themselves down for the winter. But they certainly had not 

 thriven, for they were not half the size of the other survivors — probably 

 not past the second skin. So far then as my investigations go, we 

 uuiy safely conclude that I\ smaraiidaria may well be an inland insect, 

 and that it is not confined to AftemiHia maritimn for food, but that it 

 will feed from the egg upon southernwood, wormwood, tansy, and 

 yarrow, and thrive thereupon. Probably many more food-plants will 

 be found.'' I am only concerned to make amends for ihy error of 

 observation. How it is that larvae will take to a fresh food-plant when 



* We should be glad to know whether the larvas of this species will feed on 

 GnaphnlUim . If any of our readers have the chance the experiment might be 

 made. We found the species (imagines) high up (above 5.000ft. elevation) in the 

 Daiiphine Atjis. near La Grave, among what we suspect was a bushy species of 

 (riurplialiidii, and very abundant by the roadsides in this district. — En. 

 July 1st, 1901. 



