OF THE FARM AKD GAEDEN. 



93 



remain to be considered attack it both in the larva and 

 in the perfect state, but go underground to pass into tlie 

 pupa state; in which state — like all other beetles, with- 

 out exception — they are quiescent, and eat nothing at all. 



The larva of the Three-lined Leaf -beetle may be distin- 

 guished from all other insects that prey upon the potato 

 by its habit of covering itself with its own excrement. 

 In figure 63, a, this larva is shown in profile, both full 

 and half grown, covered with the soft, greenish excre- 

 mentitious matter which from time to time it discharges. 

 Figure 63, c, gives a somewhat magnified view of the 

 pupa; and figure 63, h, shows the last few joints of 

 the abdomen of the 

 larva, magnified, and 

 viewed, not in profile, 

 but from above. The 

 vent of the larva, as 

 will be seen from this 

 last figure, is situated 

 on the upper surface 

 of the last joint, so 

 that its excrement 

 naturally falls upon 

 its back, and by suc- 

 cessive discharges is pushed forward towards its head, 

 till the whole upper surface of the insect is covered with 

 it. In other insects, which do no not indulge in this 

 singular practice, the vent is situated either at the ex- 

 treme tip of the abdomen or on its lower surface. 



There are several other larvae, feeding upon other 

 plants, which commonly wear cloaks of this strange 

 material, among which may be mentioned the larvae of 

 certain Tortoise-beetles {Cassida), some of which feed on 

 the Sweet Potato vines. (See Sweet Potato. ) 



There are two broods of this species every year. The 

 first brood of larvae may be found on the potato vine 



Fig. 63. — THEEE-LINED LEAJ'-BEETLE. 



o, Larva ; 6, End of Body ; c, Pupa ; d. Eggs. 



