170 BOARD OF AGRICULTURE. 



of these small cocoons from most of which the parasites have 

 made their escape. I have no specimen of the perfect insect at 

 present within my reach, from wliich to describe more particu- 

 larly, but it will be recognizable in all probability from the 

 foregoing figures and history, and be easily raised from the 

 cocoon and set free in the neighborhood of grape-vines infested 

 by the C/iasrocampa, or hog-caterpillar, with a view to destroy 

 them. It has been the practice in Europe, for some time, to 

 rear and scatter parasitic Hymenoptera of different species 

 among the insect enemies of various crops, which are found to 

 be their appropriate food ; this plan has been crowned with 

 noted success and I learn has already been inaugurated on 

 this side of the water, by the enterprise of the New York State 

 Agricultural Society, and when more generally published 

 among agriculturists will no doubt be found one of the most 

 simple and efficacious means of ridding ourselves of many 

 insect posts. The caterpillars containing the eggs of this and 

 similar species, may be known even before the external cocoons 

 are formed, by the small, black punctures disposed in an irregular 

 manner and plainly visible on various parts of the body. Cocoons 

 of parasites are often found of a silky white or yellow color 

 attached in a mass to stems of grass and various other plants, 

 and should never be destroyed or molested, unless it is desirable 

 to remove them to some })lace where the insect known to be 

 the food of tlieir respective tenants is more abundant, or for 

 the purpose of examination and study. 



Tiie Ap/tklii or parasites of the Aphides, (plant-lice,) are 

 generally placed in a subdivision of the ichneumons called 

 Braconidcc, and although of small size (being less tiian one 

 tenth of an inch in length) are of infinite service to the culti- 

 vator. The indefatigable State Entomologist of New York, 

 Dr. Asa Fitch, has described several new species in the agri- 

 cultural report of that State, for 1860, from which I take the 

 liberty of extracting the following descrij)tions of two, that were 

 found tlironghout Now England, contril)uting in no slight degree 

 to check the ravages of the grain-aphis, as it is called, that 

 threatened the grain crops a year or two since. 



'■'■Ajiltidius {Toxdres^ Irilicdjihis, Fitch. Wheat-louse Aphi- 

 dius. Black, shining, anteniuc thread like, longer than the 

 body, twenty-five jointed. Length, .08. Head transverse, 



