A NEW WEBWORM ENEMY OF CRUCIFEROUS PLANTS. 55 



spiracle of this segment is dark brown, the remainder being concolorous 

 with the body. The thoracic legs are more or less infuscated, and the 

 prolegs are nearly concolorous with the venter. The entire surface of 

 the body is sparsely covered with moderately long yellow and light 

 brown hairs, proceeding from small and shining piliferous tubercles. 



The anal shield bears from ten to a dozen round purplish sj)ots, the 

 most posterior one the largest and standing alone, the remainder form- 

 ing a subcrescentic pattern. 



The length when in natural position at rest is about 13 mm and when 

 extended 15 mm , the width being a trifle more than 2 mm at the widest 

 part. 



The pupa. — The pupa is moderately shining light yellowish brown in 

 color and the surface is covered with a light pruinose bloom. The eyes 

 are dark brown, varying to black and the dorsum is marked by a median 

 stripe. The contracted antepenultimate segment is noticeable. The 

 anal segment terminates in two pairs of straight brown hairs. It is of 

 rather robust cylindrical form, measuring about three-tenths of an inch 

 (7.5 mm ) in length and one twelfth (2 mm ) in width. The somewhat pecu- 

 liar outline of the abdominal segments is shown at d of figure 12. 



Transformation to pupa and thence to imago takes place in a rather 

 compact cocoon composed of white silk, which in the field is presumably 

 spun between or upon the leaves of its host plant. Those before the 

 writer measure about three-eighths of an inch (9 mm ) long and a little 

 less than half that in width. 



FURTHER OBSERVATIONS DESIRABLE. 



The egg is unknown and considerable remains to be learned of the 

 life history of this insect, its full cycle of development, the number of 

 generations produced each year, the stage and the place of hibernation, 

 a full list of crop and other plants attacked by it, its predaceous as 

 well as parasitic enemies, and other data of minor import. 



Eeasoning from analogy we may surmise that the moths make their 

 appearance early in the season and that when the first brood of larvae 

 is hatched is the best time to attack the insect with insecticides, as 

 there are probably several, perhaps as many as four generations, pro- 

 duced in the latitude where it is now located. Hence it is of prime 

 importance that this time be ascertained. 



PROBABILITY OF FUTURE SPREAD. 



From the ease with which this pest may be transported as larva, 

 pupa, or egg in heads of cabbage shipped from one place to another, as 

 well as by flight of the moth, we can predict with a fair degree of cer- 

 tainty that its further dissemination is only a matter of time. The 

 present seat of its depredations will undoubtedly become a center of 

 diffusion, from which it will soon spread by flight to neighboring locali- 

 ties and eventually, by flight from these points or by commercial 



