PREFACE. 
The present publication comprises a series of articles and notes 
brought together in bulletin form in continuation of work begun sev- 
eral years ago, the earlier results of which were published in Bulletin 
10 of the present series, in the Yearbooks of this Department for 1896 
and 1898, and in several circulars of this office. Bulletin 23 of this 
series was devoted exclusively to the subject of insects injurious to 
garden crops and Bulletin 19 mainly to the same subject. This con- 
tribution is therefore the third bulletin of the series, and is entitled 
"Some Insects Injurious to Vegetable Crops." 
The various species of noxious insects discussed have, with few 
exceptions, been destructive during the years 1900 and 1901, but a few 
came under observation at an earlier date. The work is therefore, to 
a certain extent, a report on the principal insects which haA^e been 
injurious and whose ravages have been brought to the attention of 
this office as affecting the vegetable crops of the country during the 
past two years. Circumstances beyond the writer's control have pre- 
vented the publication of this matter until the present time. 
The initial article treats of the potato stalk weevil, which has been 
very injurious for a number of years but has never received extensive 
notice in any of the publications of this Department; hence, all avail- 
able facts concerning it, together with an original illustration, have 
been brought together. The Northern leaf -footed plant-bug attracted 
more attention during the last two years than ever before in its his- 
tory, and its abundance in the vicinity of the District of Columbia 
enabled a study of its habits and the practical completion of a knowl- 
edge of its life history, the results of which are here given. 
We have to record the appearance of a new insect enemy of carrot, 
celery, and some other umbelliferous crops in this country. The 
insect in question, the carrot rust fly, has been present in Canada since 
1885. but was not known as the cause of injury to any crop plants in 
tin 1 United States until the past year, when it occasioned the ruin. of 
6,000 plants of celery on one farm in New York State. The proba- 
bilities are that this species will continue to spread and that it may 
become an important post: in fact, the most serious drawback to the 
cultivation of carrot, parsnip, celery, and other umbelliferous crops. 
Another insect now holds this distinction. It ma}' be known as the 
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