INSECTS INJURIOUS TO MISCELLANEOUS CROPS 371 



eating the thick part of the root when it is half grown, stunting 

 the plant so as to make it worthless for market. The life history 

 of the species does not seem to have been carefully observed, 

 but from analogy is probably somewhat similar to that of the 

 cabbage root-maggot, except that the maggots of the carrot 

 rust-fly develop and transform on carrots in storage if the tem- 

 perature be sufficient. 



Control. Control measures as recommended for this insect 

 have not proven of any great benefit so we must wait for addi- 

 tional information before making definite suggestions. 



The Parsnip Webworm * 

 The Parsnip Webworm is quite a common pest of the forming 



FIG. 313. The parsnip webworm (Depressaria heracliana De G.): a, moth, 

 b, c, larvae; d, pupa; e, anal extremity of pupa;/, umbel of parsnip webbed 

 together by the larvae natural size. (After Riley.) 



seed of the parsnip, but fortunately it seems to prefer wild carrot 

 as a breeding plant. It is an imported species, occurring in north- 

 ern Europe, which was first observed in this country in 1873 and 

 since then has become generally distributed over the Northern 

 States and Canada westward to the Mississippi. 



The moth is a grayish-buff or pale ochreous color, marked with 

 fuscous, the wings expanding about three-quarters of an inch. 

 The larva is a pale yellowish, greenish or bluish-gray, with con- 

 spicuous black tubercles, the head and prothoracic shield black, 



* Depressaria heracliana DeG. 

 " Insect Life," Vol. I, p. 94. 



Family CEcophoridce. See C. V. Riley, 



