41 



worms be put into a box and taken home, where they can be easily 

 watched, the cause of the sickness will soon be made out. Small white 

 magg-ots bore their way out through the skin and settle upon the 



poor caterpillar, as in Fig. 51 ; 

 and if these maggots are watched, 

 it will be found that they soon 

 begin to spin silken cocoons 

 about their bodies. The cater- 

 pillar has sometimes enough life 

 left to crawl away from its tor- 

 mentors an inch or two ; but 

 usually it dies beside them, and 

 in a day or two no trace of its 

 body can be found. If these 

 cocoons be placed in a box for a 

 few days, small four-winged flies 

 will come out through lid-like 



Fig. 51. (a) The 4-wmged fly which lays her eggs within Qpenino-S at the end. These flieS 



cabbage-worms ; (b) the maggots coming out of cab- f » „ „„,. ^f „ 



bage-worm to spin their cocoons; (c) a mass of are parasites. cy means Ot a 



cocoons; (d) cocoon enlarged showing how the fiy gg^lg „„ j^j^g hinder end of their 



comes out by raising a lid. . . r ^u 



body, they pierce the skin ot the 

 cabbage worm and lay their eggs within its body ; in a short time the 

 eggs hatch small maggots, which grow and feed within the body of their 

 host until they become full grown, when they come out as already 

 described. 



Frequently, too, some of the chrysalids, which we find in early 

 spring, are dead and straw-colored. When one is broken open, many 

 little, grayish maggots may be seen 

 to fill up the entire space within ; 

 and, if the dead chrysalids are kept 

 in a closed box for a short time, 

 many little bronze-colored flies make 

 their appearance. These flies also 

 are parasites. Their eggs are always 

 laid within the chrysalis case late in 

 the fall, and the maggots which 

 hatch from the eggs feed on the 

 body of the chrysalid. In a short 

 time they are full-grown, and fill up 

 the space occupied by the body. 



One other thing about this in- 

 sect may be noted. Its breathing 

 system is made up of tubes which 

 branch through the body and supply air to the colorless bloody The 

 openings of the tubes, or breathing pores, can be readily seen with the 

 naked eye along each side of the body in the same line as the yellowish 

 dots (Fig. 50.) 



A good practical way of killing cabbage-worms, when they are spoil- 

 ing the cabbao-es, is to dust a mixture of one pound of insect powder and 



Fig. 52. The Insect and the Boy. 



