THE CANADIAN EiNTOMOLOGIST. 51 



THE PURSLANE SAW-FLY— SCHIZOCERUS ZABRISKEI, 



ASHM., MS.* 

 BY F. M. WEBSTER AND C. W. MALLV, WOOSTER, OHIO. 



Just when this species first became abundant in Ohio we are unable 

 to say, but it was not until June, 1898, that we began a study of its 

 habits. The insect is quite generally distributed in Ohio, as we have 

 observed it at Alliance, VVooster, Tiftin, Fremont, and Clyde, and per- 

 haps over the eastern and western parts of the United States, as it is 

 found at Washington, D. C, where Dr. Chittenden is making a careful 

 study of it, and Mr. Mally observed it in abundance in the summer of 

 1899, at l)es Moines, Iowa. 



We have been informed that the species has been described by Mr. 

 .\shmead in a paper to be published " shortly."' 



Here at Wooster, not a plant could be found that was not infested, 

 including all plants in the greenhouse, by July i, 189S. it is quite 

 effective in checking the purslane, in many places the plants not develop- 

 ing seed, due to the destruction of the leaves. 



The eggs are deposited in the edge of the leaves, deposition usually 

 being completed in ten to fifteen seconds. In no case was a female 

 observed to deposit on the flat surface of the leaf, or on the stem. As 

 soon as hatched the larva; begin to feed on the leaf' and ultimately mine 

 out the greater part of the pulpy substance, but never eat through the 

 surface until driven to do so from lack of food, when they emerge and 

 make their way to a fresh leaf, immediately enter and continue their 

 mining habit, apparently not feeding on the surface at all, except as they 

 cut their way into the leaf. In numerous instances, where the obtainable 

 leaves had all been exhausted, the larv:e bored downward in the stems of 

 the plant. The larvte do not drop readily from the surface of the plant, 

 and, when handled with forceps or needle, they exude a clear viscid sub- 

 stance which holds them in place. 



When fully developed, the larv* enter the ground to the depth of 

 one-half to one inch and form a silken cocoon, to which bits of soil 

 adhere quite firmly, and there transform. The pupa stage lasts only 

 about seven days, when the adults emerge, a few males m advance, soon 

 after which the sexes pair and oviposit. 



In nine cases out of ten distinct experiments in the insectary, in 

 rearing the adults, the time of the larva entering the soil, and the 

 '" * Read l)cfore the Ohio Academy ot Science, December 22, 1899. 



