REPORT OF THE ENTOMOLOGIST. 243 



any discoloration, even where the effects of the punctures were visible 

 from slight swellings or callosities. 



In the perfect state, however, the female is capable of doing great in- 

 -jary to trees in ovipositing, and although this injury in the forest is 

 immaterial, it may become very serious in orchards, and is of still more 

 consequence in the nursery. 



Having tried fully, without success, in 1868, in Missouri, such insecti- 

 cides as promised practical results in repelling the mature insects from 

 IVuit trees, we had not much hope of more satisfactory results from any 

 Ivirtlier trial. Yet we desired to test the effect and value of such iu- 

 st'ctic'ide substances as have come into use since that time, and for that 

 reason planned and had a series of experiments executed. Mosb of 

 these experiments were intrusted to Dr. W. S. Barnard, and we give 

 herewith the results : 



Destruction of the Insects as they issue from the Ground. 



I*yrethrum Foicder. — This proved a perfectly satisfactory destroyer of 

 the Cicadas vhen freshly emerged and soft, and also when mature and 

 hardened, both in the dry part of the day and when the dew was on them. 

 It is easy to puff this powder on them when on grass, weeds, and trees 

 in the morning before they gain full strength and ascend. At this time 

 most of the insects are so low on the trees, or so near the ground, that 

 it is easy to make the powder reach them while standing on the ground. 

 It seems to be the most easy and convenient way of killing them. It 

 was thus applied to them on the lower branches and trunks, also to 

 groups of them collected and placed at stakes in thfe grass and at the 

 bases of uninfested trees. In each instance all except the pupa3 died 

 of it sooner or later. Oft-repeated tests showed it to be practically 

 worthless against the pupae, for even when thoroughly coated with 

 powder they would give forth the perfect insect. But the winged insects 

 are quite sensitive to the powder, showing marked irritation from it 

 within five minutes after treatment. Though hanging quietly when pow- 

 dered, uneasiness soon appears in the movements of the limbs and occa- 

 sional strokes of the wings against the sides. The movements of the 

 legs appear to be uncontrollable, so that in the course of a few hours the 

 insect falls helpless to the ground, where, though the movements may 

 continue for a whole day before death, a fatal termination is sure to 

 follow. The powder was tested on ten different lots of Cicadas, includ- 

 ing about four hundred specimens (100 pupse, 200 soft or forming adults, 

 100 full-fledged adults). 



In one experiment a ring of pyrethrum powder about one-eighth of 

 an inch deep and 2 inches wide was placed on the ground around a tree 

 trunk. The pupai marched through this and ascended and molted with 

 safety; but the winged insects that had fallen, and others from the 

 grass on which they had emerged, were stifled by the pyrethrum as 

 they tried to ascend tbe tree. 



In testing the pyrethrum powder on pupse, in most instances none 

 died; but in two of the tests 10 per cent, of the pupae died, but there 

 was reason to believe that d6ath resulted in these instances from hand- 

 ling and collecting them in masses. 



JPyrethrum Water. — This was prepared in two ways, (1) by stirring 

 into water as much pyrethrum powder as the water would suspend 

 when at rest; (2) by adding milk (1 pint) to pyrethrum (4 fluid ounces), 

 and afterward diluting to suit. The milk, even when soured, holds aii 

 the powder in suspension, and facilitates its suspension in water. 



