The Bulletin. 9 



a small pointed beak by means of which the stem or leaf is pierced, and 

 the sap is then withdrawn. Cabbage are not "eaten up" by the cabbage 

 louse, they are rather sucked to death, and .the difference is important, 

 as is shown in the discussion of remedies. 



The louse attacks many different kinds of plants related to cabbage, 

 records in this ofhce showing complaint of its injuries to collard, ruta- 

 baga, radish, and turnip. It is commonly seen on mustard in spring. 

 It will no doubt attack kale and cauliflower just as readily. 



The breeding habits of the cabbage louse are interesting, and in this 

 it is like many other kinds of plant lice. In the first place let it be under- 

 stood that the cabbage louse is always a louse, it never is a butterfly, or a 

 worm, or a caterpillar, and no kind of moth or butterfly lays eggs to 

 make lice. The full grown cabbage louse is never more than about one- 

 eighth inch long, and it may be either winged or wingless. All through 

 spring and summer the full grown females (whether winged or not) give 

 birth to living young, and the young lice are in all appearances similar 

 to the old ones except that they are smaller and are of course without 

 wings. But in the fall there is a generation of full grown females which 

 may develop eggs, and these eggs may pass the winter. The writer is not 

 sure that all these details have been fully worked out in the Southern 

 States. Personally he is inclined tc '\?lieve that the grown lice and young 

 lice, too, may pass our mild winicrs alive on the plants. At any rate all 

 ages of living lice are to be found in great numbers on the plants in 

 late winter and early spring. 



The wingless lice can of course move only for short distances and can 

 not spread the species very widely, but by being confined to the one 

 plant on which they grow they do certainly result in very bad infesta- 

 tion of those plants. But when a plant is crowded the winged ones 

 can fly away to new plants and there start new colonies and work new 

 damage. Indeed, when a plant becomes crowded it seems as if a 

 greater number do develop wings, so that nature thus enables them to 

 escape starvation. 



Natural Enemies. — There are a number of other insects which at- 

 tack and kill the cabbage louse, and they are to that extent helpful to 

 the cabbage grower, and are deserving of such protection and encourage- 

 ment as he can give. 



_ If one Avill closely examine plants Avhich are infested he will some- 

 times find among the healthy, active lice a considerable number that 

 are dead, dried and bloated in appearance. A few such can be found in 

 Figure 1. Some of these will have a little hole cut in the body, usually 

 on the back. These lice, have been parasitized, that is they were stung 

 by a tiny little four-winged insect not unlike a wasp or bee, but so small 

 that it could grow to its full size inside the body of the louse. When 

 this little insect stung the louse, it laid an egg in the skin or body of 

 the louse. That egg hatched to a tiny maggot or grub which lived 

 inside the body of the louse. As it grew to maturity the louse sickened 

 and died and the body swelled up as described. Then the maggot went 

 through its changes to a little four-winged insect (like that which first 

 stung the louse), it cut its way out through the back of the louse, and 



