32 CLOVER. 



The amount of infestation was enormous, and it is of some practical 

 interest to refer again to the attack, just to note that though the most 

 serious destruction (of which we have record) which was caused on 

 their way by the caterpillars of the migrating hordes was to Sugar 

 Beet in Saxony, yet of the " hundreds of thousands " of the moths 

 reported at Osteud, these were mentioned as being principally on some 

 Clover ; and in this country, although the caterpillars were exceedingly 

 injurious (as at Exeter, where they were noted by Mr. Edw. Parfitt as 

 literally swarming on every garden plant, and defoliating the plants as 

 well as riddling the leaves), yet, so far as I can find, the only crops 

 which suffered were Peas, as for instance near Chichester, where it was 

 observed " whole fields of Peas " were well-nigh stripped bare by the 

 caterpillars. 



In the past season some observations were again forwarded to me 

 regarding severe injury from the Gamma caterpillars to Clover in 

 different localities, the caterpillars in two instances (when they had 

 devoured all that suited them of the Clover) being noted as migrating 

 onwards, in one place to Potatoes ; in another, some to Potatoes and 

 some to neighbouring Hops ; and in another locality they were noted 

 as passing on from Clover to Eape, Swedes, and Mangolds. The eggs 

 are generally laid beneath the leafage. 



The caterpillars are in part recognizable by being " half-loopers," 

 what are technically called "semi-geometrical larvae," that is, they have 

 two pairs of sucker-feet beneath the body, whereas the true loopers 

 have only one pair, in addition, in both cases, to the pair at the end of 

 the tail. Consequently, though they form an arch in walking, as 

 shown in the figure at p. 31, they do not make a complete loop. The 

 colours vary with age ; at first they are stated to be very dark deep 

 green with a mixture of brown, and when they are older they are con- 

 sidered to vary in tint with the colour of the leafage on which they 

 feed, this presumably from the consumed leafage showing through the 

 transparent skin. In this country it was considered by Curtis that 

 after moulting several times, they became of a green colour, with a 

 greenish -brown head. They have six fine whitish lines along the back, 

 and a yellow line along each side, and are covered with short hairs. 

 The sucker-feet are green, the claw-feet green or reddish-brown. 

 When full-fed they spin a light woolly cocoon on a stem, or attached 

 to a leaf. The latest brood winters, or may winter, in caterpillar state, 

 and comes out again in spring to complete its growth, and, with us, 

 the moth is present during summer and autumn. 



The moth is about an inch and a half, or rather more, in the 

 spread of the fore wings, which are of a satiny shine, variegated with 

 coppery, grey, and brown, and marked in the centre with a bright 

 silvery mark something like the letter " Y," whence the moth takes 



