476 



INSECTS INJURIOUS TO VEGETATION. 



chaffy scales of the grain. Being hatched at various times 

 during a period of four or five weeks, they do not all arrive at 

 maturity together. Mrs. Gage informs me that they appear 

 to come to their growth in twelve or fourteen days. They do 

 not exceed one eighth of an inch in length, and many, even, 

 when fully grown, are much smaller. From two to fifteen 

 or twenty have been found within the husk of a single grain, 

 and sometimes in every husk in the ear. In warm and shel- 

 tered situations, and in parts of fields protected from the wind 

 by fences, buildings, trees, or bushes, the insects are said to be 

 much more numerous than in fields upon high ground or other 

 exposed places, where the grain is kept in constant motion by 

 the wind. Graifi is commonly more 'infested by them during 

 the second than the first year, when grown on the same ground 

 two years in succession ; and it suffers more in the immediate 

 vicinity of old fields, than in places more remote. These in- 

 sects prey on the wheat in the milky state, and their ravages 

 cease when the grain becomes hard. They do not burrow 

 within the kernels, but live on the pollen and on the soft mat- 

 ter of the grain, which they probably extract from the base of 

 the germs. It appears, from various statements, that very 

 early and very late wheat escape with comparatively little 

 injury; the amount of which, in other cases, depends upon 

 the condition of the grain at the time when the maggots are 

 hatched. When the maggots begin their depredations soon 

 after the blossoming of the grain, they do the greatest injury; 

 for the kernels never fill out at all. Pinched or partly filled 

 kernels are the consequence of their attacks when the grain is 

 more advanced. The hulls of the impoverished kernels will 

 always be found split open on the convex side, so as to expose 

 the embryo. This is caused by the drying and shrinking of 

 the hull, after a portioai of the contents thereof has been 

 sucked out by the maggots. Towards the end of July and in 

 the beginning of August, the full-grown maggots leave off 

 eating, and become sluggish and torpid, preparatory to moult- 

 ing their skins. This process, which has been alluded to by 

 Judge Buel and some other writers, has been carefully observed 

 by Mrs. Gage, who sent to me the maggots before and after 



