104 STATE POMOLOGICAL SOCIETY. 



But I will illustrate the parasite theory of the insect world by 

 showing you the tomato worm. (Here the lecturer illustrated, at 

 some length, the curiosities of parasitism by means of drawings 

 on the blackboard, which cannot be produced here.) There is a 

 peculiar little raicrogaster, a little fly that comes along and inva- 

 riably settles on the back or head of the tomato worm, knowing 

 very well that it cannot there be injured. It punctures the skin 

 of that worm and inserts an egg, or perhaps forty or fifty. The 

 maggots hatched from these eggs feed on that worm, which ia 

 time becomes sickly, until at last the little parasites are fully 

 grown, and then they spin cocoons on the back of the worm, from 

 which eventually little black flies, like the parent, issue. Now, 

 this is primary parasitism ; but there are secondary, tertiary, and 

 even quartenary parasites. And so it is, in the language of Swift : 



' So naturalists observe a flea 

 Has smaller fleas that on him prey; 

 And these have smaller .«till to bite 'em, 

 And so proceed, ad infinitum.' 



We frequently have no less than four distinct parasites feeding 

 on one another, and all of them on a vegetable feeder. True par- 

 asites, as distinguished from cannibals, invariably and necessarily 

 are much less in size than those upon which they prey. I have 

 mentioned two parasites on this apple-worm. I will try to describe 

 one; it is the Macrucentrus delisalus. This fly punctures the worm 

 while yet in the heart of the apple, and spins its cocoon inside the 

 cocoon of the apple worm. This is a yellow fly; the other is a 

 black fly, Pimpla anniilipes. Instead of destroying it before it has 

 assumed the chrysalis state, it does not destroy it until after. 



Besides these, I know that two cannibal beetles — the PennsyJ- 

 vauia soldier beetle, and the two-lined soldier be(!tle, as well as 

 the ants and cockroaches — destroy it as it leaves the fruit. Then 

 there is a species of Irarjosila, which Dr. Le Baron and I have found 

 in the bandages, destroying the worm. I mention this to show 

 that it has its enemies notwithstanding that it lives iu the centre 

 of the apple, and descends from the tree at night. 



With regard to liquids and lights, they are of no practical im- 

 portance. Both modes kill as many of the enemies of the codling 

 moth as of the moth itself. The moth has a short tongue, and may 

 feed to a slight extent on liquid sweets, but that it is attracted by 

 them I do not believe ; but certain kinds of beetles which prey 

 upon it are so attracted. The codling moths are attracted by lights 

 very slightly indeed. If you have a light in the orchard, and some 

 way to secure them, you will find a few of them among hundreds 

 of other species. They are very rarely found around our lamps. 

 I have tried it, and even where insects pattered on my windows, 

 making a noise like a hail-storm, and got into the room, 1 would 

 ver3' .rarely find codling motiis among them, though I knew they 

 were abundant in apple trees infested by them not two rods away. 

 It is of prime importance to destroy the winter cocoons in our cel- 

 lars and storehouses. The necessity of destroying them becomes 

 apparent, because we keep them out of the way of the natural 

 enemy that might otherwise destroy them. In the spring all the 



