ONE HUNDRED THOUSAND FACTS FOR THE PEOPLE. 365 



like all other beetles, without exception — 

 they are quiescent, and eat nothing at 

 all. 



The larva of the Three-Lined Leaf- 

 Beetle may be distinguished from all 

 other insects that prey upon the potato 

 by its habit of covering itself with its 

 own excrement. In figure 8, this larva 

 is shown in profile, both full and half 

 grown, covered with the soft, greenish 

 excrementitious matter which from time 

 to time it discharges. Figure 7 gives a 

 somewhat magnified view of the pupa; 

 and Figure 8 shows the last few joints 

 of the abdomen ot 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 successive discharges is 

 pushed forward towards its head, till the 

 whole upper surface of the insect is 

 covered with it. In other insects, which 

 do not indulge in this singular practice, 

 the vent is situated either at the extreme 

 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 one which is 

 very common upon the Sumach, and 

 which produces a jumping, oval Leaf- 

 beetle, about a quarter of an inch long, 

 and of a yellow color, speckled with 

 brick-red. The larvae of certain Tortoise- 

 beetles, some of which feed on the 

 Morning Glory and the Sweet Potato 

 vines, adopt the same practice, but in 

 their case there is a forked process at the 

 tail which curves over their backs and 

 receives the requisite supply of excre- 

 ment. 



There are two broods of this species 

 every year. The first brood of larvae 

 may be found on the potato vine toward 

 the latter end of June, and the second in 

 August. The first brood stays under- 

 ground about a fortnight before it emerges 

 in the perfect beetle state; and the 

 second brood stays there all winter, and 

 only emerges at the beginning of the 

 following June. The perfect beetle is of 

 a pale yellow color, with three black 

 stripes on its back, and bears a general 

 resemblance to the common Cucumber- 



beetle. From this last species, however, 

 it may be readily distinguished by the 

 remarkable pinching in of the sides of 

 its thorax, so as to make quite a lady-like 

 waist there, or what naturalists call a 

 " constriction." It is also on the average 

 a somewhat larger insect, and differs in 

 other less obvious respects. As in the 

 case of the Colorado Potato-beetle, the 

 female, after coupling in the usual man- 

 ner, lays her yellow eggs (Fig. 8) on the 

 under surface of the leaves of the potato 

 plant. The larvae hatching from these 

 require about the same time to develop, 

 and when full grown descend in the same 

 manner into the ground, where they 

 transform to pupae (Fig. 8) within a small 

 oval chamber, from which in time the 

 perfect beetle comes forth. 



The Three-lined Leaf-beetle, in certain 

 seasons, is a great pest in the Eastern 

 States ; but, it has never yet occurred in 

 the Valley of the Mississippi in such 

 numbers as to be materially injurious. 



APPLE-BOOT PLANT-LOUSE.— The 

 roots of the apple tree are very often 

 found to rot, and thus cause the death of 

 the tree. Of these rots there appear to 

 be three distinct kinds. One kind is that 

 popularly known as "rotten root" in 

 Southern Illinois, and seems to be a 

 simple decomposition of the vegetable 

 tissue, analagous to the rotting of the 

 root of a cabbage, for instance. Its 

 cause is not clearly understood, though 

 it seems to be a consequence of certain 

 conditions of the soil. The other rot 

 was discovered during 1875, by Doctor 

 Hull, of Alton, Illinois, and is a fungoid 

 growth, which, after covering the root 

 with a thin layer of white fibrous sub- 

 stance, causes a sort of dry rot of the root, 

 and which is common to both the pear 

 and the apple. Some of the symptoms 

 of this rot are : a rather earlier develop- 

 ment or maturity of the branches ; an ex- 

 cess of fruit buds, and a shortening or 

 thickening of some twigs. 



Although this insect usually confines 

 itself to the roots of the tree, yet a few 

 may occasionally be found on the suckers 

 that spring up round the butt of the 

 trunk, and even on the trunk and limbs, 

 especially in places where a branch has 

 been formerly amputated, and nature is 

 closing up the old wound by a circle of 

 new bark. Where it works upon the 



