The Canadian Horticulturist. 441 



Parasite of the Tomato Sphinx. 



590. Sir, — I send to your address a specimen of a tomato worm, winch I believe 

 to be a female, with some of the eggs attached. From their appearance under the glass, I 

 am led to suppose that after a certain time these eggs are deposited in the ground, where 

 they hatch out the following season to pursue their destructive work among the tomato 

 plants. Kindly give through the Journal any information you can command on this 

 subject and favor 



Geo. C. Moore, Eglinfon, Ont. 



Reply by Prof. Fletcher, Entomologist, Central Experimental Farm, Ottawa. 



The objects taken by Mr. G. C. Moore for the eggs of the Tomato Worm 

 are really the cocoons of a beneficial parasite belonging to the same class as the 

 Wasp and Ichneumon flies. The eggs from which the tomato-worms come are 

 laid by a large moth. It is sometimes very abundant, but when this is the case, 

 many of them are usually destroyed by this parasite, which is known by the 

 name of Apanteles congregatus. The eggs of this insect are laid by the female 

 fly within the body of a caterpillar by means of a needle-like ovipositor, with 

 which she pierces the skin. Sometimes as many as 200 eggs are laid in a 

 single caterpillar (207 cocoons of this parasite were actually counted on a large 

 specimen of the Tomato Sphinx found in London, Ont.) The young maggots 

 upon hatching feed upon the fatty parts of their victim and, when full-grown, 



force their way through its skin, and work them- 

 selves out as far as the last joint of their bodies, 

 when they begin spinning their small white 

 cocoons, which stand on end and present the 

 Fig. 408.— Cocoons of A. congre- appearance of the figure. From these eventually 

 gatm on Sphinx caterpillar. the small actiye black four-winged flies emerge. 



I may mention that it is a common mistake for those not acquainted with 

 entomology to take these cocoons for eggs, but eggs are only laid by insects in 

 the perfect state. 



The Fertilizing" Value of Spent Hops. 



591. Sir, — Would spent hops from breweries be good on heavy clay land, cultivated 

 as a vegetable garden ; also in a plantation of apples, pears and small fruits ? If so, how 

 would yon apply it, and in what quantities ? 



Fred Hoskie, Port Colborne. 



Reply by Prof. Shult, Chemist, of Central Experimental Farm, Ottawa. 



In hop refuse the more valuable constituents of plant food, viz., nitrogen, 

 phoshporic acid and potash, are present in such small quantities that, considered 

 as a fertilizer, this material cannot be looked upon as possessing any commercial 

 value. 



