26 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



foliage of these j^lants, but Glover states that they sometimes feed 

 upon the petals of the flowers of cotton, althoua'h doing little harm 

 to the general crop. 



THE INSECT'S LIFE HISTORY. 



Our knoAvledge of the life history of this species is somewhat 

 incomplete. The repeated rearing of moths in early spring and the 

 occurrence of larva^ in the latter part of June in Massachusetts as 

 recorded by Smith, as also in the District of Columbia and elsewhere 

 as late as October, noted by the writer and others, show at least two 

 generations in the Northern States, while the record of the occur- 

 rence of the moths in March in Texas (by Belfrage) would indi- 

 cate that in the (lulf States there may be an additional generation. 

 It vvould seem practically impossible for larvcV hatching from eggs 

 deposited in early spring to require until late October to attain 

 maturity, hence the natural inference of two generations for a 

 climate like the District of Columbia. The cranberry growers of 

 Massachusetts claim two generations for that State, one appearing 

 as larvir in June and early July, the other in the latter part of 

 August. 



The eggs are unknown, and the periods of egg and larva have 

 not been ascertained, but the pupal condition has been observed to 

 be passed, for the first generation, in from 11 to 14 days, while the 

 over-Avintering pupa consumes five or six months in the District of 

 Columbia, a shorter time farther south, and a longer time northward. 



The date of the appearance in the North of the first moths has 

 not been learned positively nor the natural time of emergence of the 

 first new generation of moths. 



NATURAL ENEMIES. 



Doctor Smith ' has stated that the larva^ of this spanworm are 

 checked by parasites, but that in some localities almost every year 

 they become numerous enough to be destructive. In some, years, 

 however, in the cranberry bogs of New Jersey they are not seen at 

 all, showing great scarcity, due probably in part, at least, to natural 

 causes. Only one parasite for this species is known, namely. Ex- 

 orista hoarmUc Coq., a tachina fly reared at this Department from 

 Cotuit and other localities in Massachusetts several years ago. 



REMEDIES. 



This species is not difficult to control on asparagus or other truck 

 crops. As it feeds in free exposure on the foliage, spraying with 

 Paris green or arsenate of lead will destroy it. and when either of 

 these insecticides is used for the asparagus beetles it will kill all of 

 the spanworms which may be present. The Paris green may be 



