178 LETTERS TO MESSRS. COLEMAN [CHAP. xvn. 



from clover. It is too late to-night to give you a detailed 

 account, but I write now, as you will be interested to have 

 the identification as soon as possible. 



August 5, 1900. 



Your potato attack is, as I mentioned last evening, 

 caused by the caterpillar of the Silver Y-moth, so named 

 from a small bright mark on the fore-wings, in shape like 

 the English Y or the Greek Gamma. The moth is about 

 half an inch in the spread of the fore-wings, which have a 

 satiny lustre and are varied with rich coppery, as well as grey 

 and brown, marks. The hinder wings are greyish, with a 

 brown border. The caterpillars are fairly recognisable by 

 being what are called "half-loopers." Having only two 

 pairs of sucker feet beneath the body (besides the customary 

 claw feet) they form a slight arch when they walk. The 

 attack is occasionally very destructive and is one of those 



i, Eggs ; 2, caterpillar ; 3, chrysalis in cocoon ; 4, moth. 



FIG. 40. GAMMA OR SILVER Y-MOTH, PLUSIA GAMMA, LINN. 



which we have proof of having been blown to us, in moth 

 condition, from the Continent ; and, from some information 

 which has come to my hands since I received your letter, 

 I think it is not at all unlikely such may be the case now, 

 with another kind of crop. The caterpillars feed on many 

 plants, those of the cabbage and turnip kind especially ; 

 also on Leguminosce, as peas and beans. Sugar beet they 

 are destructively partial to. I should not at all think that 

 the attack was likely to recur to potatoes, or that, as the 

 infestation is now past its destructive stage, it was worth 

 troubling yourselves about. If you should desire more 

 about it than I can easily condense into a moderate letter 

 space, you would find a careful account of the attack, with a 

 good figure, in my sixteenth Annual Report on Injurious 

 Insects. Hoping, however, that my few notes may be all 

 you require, yours truly, ELEANOR A. ORMEROD. 



