EXPERIMENT STATION REPORT. 579 



double point will be gained. The date of drawing the water in spring 

 is less important, but late holding is better than early drawing. 



Where wormy berries are picked and get into the storehoaise the 

 larvfe will emerge when they are fully developed and will find some 

 crevice or shelter in wliich they will spin up and attempt to complete 

 their development.', It will be the part of wisdom to furnish plenty of 

 shelter for them in the way of loosely-piled slats or boards, which can 

 be burned during the winter. Boxes and trays can be examined and 

 cleaned of cocoons, and the cranberry-house itself should be thoroughly 

 cleaned out. But even if nothing is done, few of the larvae tempted 

 to spin up indoors come to maturity. They need moisture in spring 

 when ready to pupate and die when kept dry. 



Mr. Thayer records that cocoons were found in late fall in great 

 numbers in spaces between floor boards, but that the field mice cleaned 

 them nearly all out before the next following spring. 



THE ONION MAGGOT. 



Pcgoimjia cepetorum Meade. 



This is really only one of several species that feed in the onion 

 bulb, .and is an imported or introduced form, but in New Jersey the 

 other kinds are not common, and one, at least, seems to follow injury 

 caused by some other agency rather than act as first cause. 



Hibernation is in the adult or fly stage, in bams or among rubbish 

 and other shelter, largely in the places where onions are stored, and 

 activity begins in spring as soon as the weather becomes settled. This 

 hibernating adult somewhat resembles the ordinary hofise fly in ap- 

 pearance, and may be mistaken for it, but it is much paler, gray or 

 yellowish in color, with prominent, black bristles, and in shape it is 

 rather narrower, more elongate and more cylindrical. 



These flies are in the field as soon as the young onions begin to 

 develop, and lay their elongate, whitish, almost spindle-shaped eggs 

 in little masses at the base of the plant ; if possible, a little below the 

 surface if there is an opening. There is no horny, egg-laying tube, so 

 the insect cannot pierce the growing tissue, nor can it force its eggs 

 into the soil ; but there is a short, extensile and flexible ovipositor, by 

 means of which it takes advantage of any opening or crevice that may 

 exist around the stalk. 



