22 THE CANADIAN ENTOMOLOGIST. 



the grass and plantain leaves, seldom placing more than five eggs in one 

 cluster. Shortly after hatching the larvae ate the parenchyma of the 

 blades of grass, leaving the veins untouched ; after increasing somewhat 

 in size they fed upon the plantain leaves. The first larva of this brood 

 began spinning its cocoon on the evening of June i6 ; it became a chry- 

 salis June 19, disclosing the imago June 28. The chrysalis could easily 

 be seen through the thin cocoon. When this larva began spinning its 

 cocoon the other larvae of the same brood, hatched out at about the same 

 time and reared under precisely similar conditions, were of all sizes from 

 those only one-half grown to those nearly full grown. As they appeared 

 to be costive, I supposed that it was caused by a lack of water ; accord- 

 ingly I wet a few leaves and fed them to the larvae, shortly after which 

 they were taken with a violent scouring, which so reduced them that all 

 but one died ; this one spun its cocoon and went on to chrysalis, but died 

 before producing the imago. 



On the 6th of July following I obtained another laying of eggs, and 

 the larvae from these showed the same variation in size as those of the 

 first brood. When some of them became nearly full grown they were 

 attacked with a disease which cause3 them in a short time to turn black ; 

 if handled after death the skin readily broke, showing the interior to be 

 filled with a blackish liquid. As soon as this disease made its appearance 

 I removed the healthy larvae to new breeding-cages, but they all finally 

 died of this disease. 



On the 23rd of April, 1879, I obtained a larva of this species which 

 spun its cocoon the next day, disclosing the imago May 20 ; the earliness 

 of the date precludes the possibility of its having issued from the egg the 

 same season. It was taken while feeding upon dandelion leaves ; I have 

 taken other larvae of this species upon the leaves of burdock and plantain. 

 Prof. G. H. French states* that they also feed upon the leaves of the 

 thistle and hollyhock, but I have never taken them upon either of these 

 plants. I have seen caterpillars which did not differ materially from those 

 of precationis feeding upon cabbage leaves, and the precationis larvae in 

 my breeding-cages fed readily upon these leaves. As there is so much 

 difi^erence in coming to maturity among the larvae of the same brood, it is 

 evident that no given number of broods are reared in one season by all 

 of the members of this species ; four broods in a season seem to be the 

 maximum number, while the average number is probably three. 



* Seventh Report St. Ent. 111., p. 229, 



