The Cabbage Root Maggot. 507 



stalk on the soil and are readily seen with keen eyes. In 1887, 

 Prof. Cook recorded finding hundreds of eggs about a single 

 plant. This is no exaggeration, for we have found at least 300 

 maggots at work on a single cabbage plant. 



Several flies must lay their eggs on one plant to produce such a crop of 

 maggots ; and when only lo or 20 maggots occur, a single fly must oviposit 

 on several plants. This statement is based on the following observations. 

 April 9, a female Cabbage Fly emerged in a cage in which young cabbage 

 plants were growing here at the insectary. She laid no eggs, and died on 

 April 13. An examination was made of the contents of the abdomen, and 

 it was found to be packed full of eggs. Fifty-five of these, apparently fully 

 developed, eggs were removed one by one, before the abdomen was emptied ; 

 no partly developed eggs were seen. Thus 55 is probably about the normal 

 number of eggs laid by one fly. 



Although the eggs are very small, measuring only .04 of an 

 inch (i.i mm.) in length, their whitish color renders them quite 

 easily seem by keen eyes, lying as they do close to the stem of the 

 plant with the dark soil as a background. One of these eggs is 

 shown greatly enlarged at a in figure 8. The minute 

 hair line near the centre of b represents the natural 

 length of an ^^'g. b in the figure represents, in out- 

 line, the shape of the ^"gg when viewed from the 

 side. When examined under a microscope the 

 ^•gg shell presents the curious irregularly ridged 

 appearance as shown at a in the figure. The figure %-a thee 

 also shows the large deep groove which runs along greatly en tagged; 



o r o o the hair hne near 



its whole length becoming deeper as it approaches ''"' cetiter of b 



° or A 1. represents its nat- 



the blunter or head end of the ^gg. «'«/. length, b, 



"'^ outline of side 



Apparently all writers have followed Taschenberg Tiewofan egg. 

 (1865), in stating that the eggs hatch in about ten days. Mr. P. 

 H. Scudder, of Glen Head, Long Island, who has observed this 

 pe.st closely, told the writer that the eggs hatched in from four 

 to ten days, depending upon the conditions of the weather ; a 

 cold spell retarding their hatching. Eggs began to hatch in 

 Mr. Reeve's field at Mattituck, L,. I., this year about May 8. 



May IT, he sent us many of the eggs ; they were sent in a box nearly full 

 of soil, and reached us in seemingly good condition. They were at once 

 isolated on pieces of dampened blotting paper ; but not an egg hatched. 

 This would indicate that the eggs are easily injured if much disturbed ; and 

 t may explain the success of one of the remedial measures to be discussed 

 ater. 



