30 
opportunity to make obseryations in the field. As the larvee go deep 
into the ground upon the approach of cold weather it is quite probable 
that they may be able to survive as such. 
In any case, the insect develops rather early in the season. Attack 
begins with young carrots which turn of a rusty color, and upon 
examination the roots will be seen to be disfigured with rusty patches, 
more especially toward the tips. Both flies and maggots are found 
throughout the warmer months, but the latter desert the roots for 
pupation in the earth, the last generation probably descending much 
deeper into the earth than the earlier ones. According to Curtis the 
summer generations develop in three or four weeks. No one appears 
to have surmised how many generations are produced. There must 
be at least two, and probably more. Miss Ormerod states that the fly 
goes down into the ground for oviposition where she can find a crack 
or other opening about the roots of the carrot (or other food plant 
affected), and the maggots when hatched work their way into the roots; 
when this is quite small they often destroy the lower portion. 
NATURAL ENEMIES AND ASSOCIATES. 
Curtis found a species of parasitic four-winged fly which he described. 
as Alysia apii (Farm Insects, p. 420), and which he presumed was a 
parasite of this species and connected with its economy. 
Polydesmus complanatus Linn. is stated by Curtis to be attracted to 
the roots, which have been previously perforated by the maggots of 
this species, sometimes congregating in such vast numbers that he sup- 
posed that it was this creature which was reported to have devoured 
‘arrots by the acre in Scotland in 1831. This is a European milli- 
pede several times reported to be introduced in this country," and 
it is sometimes accompanied by a centipede known as Scolopendra 
electrica, said to assist in depredations. 
“Prof. O. F. Cook, who is our best American authority on the Myriapoda, informs 
the writer that, although this species has been recorded as occurring in the United 
States, it has not yet been positively recognized on this continent, he having never 
seen specimens. It seems probable that notwithstanding the fact that this insect 
must have been brought to this country in potted plants and in earth perhaps thou- 
sands of times, it has, for some unknown reason, failed to gain a permanent foothold. 
In response to the inquiry of the writer as to whether any of the Myriapoda, better 
known as thousand-legged worms, miillipedes, etc., were capable of original damage 
to plant tissue, Professor Cook stated that their mouth-parts were not formed either 
for biting or chewing, and that they were only capable of eroding or scraping dis- 
eased tissue, and, to some extent, soft, delicate plants. In this way, however, they 
can do oceasional damage by constantly scraping plant growth like the tubers of 
potatoes affected with scab and similar diseases, and young, delicate plants that might 
recover if they were not attacked. 
