TRANSACTIONS OF OALESBTJRG HORTICULTURAL SOCIETY. 361 



PAPER ON ENTOMOLOGY.* 



BY MISS EMILY A. SMITH. 

 THE ROSE-SLUG. 



It is no uncommon sight to see rose bushes with their leaves yellow and dried. 

 When uncovered in early spring, they promise a good supply of roses and send forth 

 buds in abundance, but in a shcrt time the leaves commence turning yellow, and ihe 

 roses are dwarfed and burst unevenly, and without the usual fragrance. This is such 

 an annoyance to the ladies that I would propose giving a simple means of obviating this 

 difticulty, and, if put into practice, will save all inconvenience the coming summer. 

 Before combating with the enemy we would do well to learn what it is that is working 

 such mischief. In 1840 the Massachusetts Horticultural Society offered a premium of 

 Sioo for the most successful mode of destroying the object of so much trouble to the 

 roies. Many persons, Harris included, commenced making investigations, and found 

 the destruction was caused by an insect. The habits, briefly stated, are as follows: Early 

 in the spring small black insects resembling flies somewhat, but different in having four 

 membraneous wings, can be seen flying about the roses, the females more sluggish in 

 their movements than the males. The females when about to deposit their eggs 

 unsheath their saw-like ovipositor, thrusting it obliquely into the skin of the leaf, depos- 

 iting in each incision one egg. The eggs hatch in ten days or a fortnight after mtu 

 small caterpillar-like worms. They have a small, round, yellowish head with a black 

 dot on each .side, and are provided with twenty-two short legs. The body is green, 

 pale above, paler at the sides, and yellowish beneath. They are sluggish in their move- 

 ments and eat mostly during the night, resting on the under side of the leaf during 

 the day, although they may be seen on the upper side during the dark, stormy days. 

 In the evening they appear and eat the upper surface of the leaf in large irregular 

 patches, leaving the veins and the skin beneath untouched, and often appear in such 

 .numbers that not a single leaf on the bush is spared by them, and the entire foliage 

 looks as if it had been scorched by fire. These worms cast off their skin several times, 

 leaving it fastened to the leaves. After having reached their full size they leave the 

 bushes by either crawling down the stem or rolling up and dropping off. When the 

 ground is reached they burrow to the depth of one inch or more in the earth, when 

 each one makes for itself a small oval cell, with particles of earth cemented with a 

 little gummy silk, and change inside to the chrysalis, appearing again as saw-flies later 

 in the season, to ccmmence again the same round of existence the same season; ihus 

 appearing as worms twice in one summer. The insect is known to entomologists as the 

 Selandria rosa: (Hr.rris.j 



From the above it is obvious the time to reach them is during the larval or cater- 

 pillar state. This can best be done by direct application to the bush infested. Many 

 good remedies have been suggested, and considerable attention has been given as to 

 which is the best. White hellebore used as a solution is well recommended, one-eighth of 

 a pound to three gallons of water, well mixed, and well applied with the watering-pot. 

 I have found, by experiment with our own rose bushes, that dusting the bushes just 

 after a rain, or when the dew is on the leaves, with sulphur, applied dry in the powdi r, 

 is an easy and effectual remedy. The insects eat the sulphur with the leaves, and sicken 

 and die in a short time after. The application is made by means of a pair of bellows, 

 kept for such purposes, and is preferred, since the underside of the leaf can be reached. 

 It can be applied quite as effectually, however, by using a common sieve. The time to 

 make the first application is about the middle of May, and, if proper attention is given, 

 the roses will be spared the ravages of the worms, and more than repay the trouble 



*The first part of this interesting paper was devoted to the natural history of ihe 

 European Cabbage-worm {Pieris rapcc); but since almost the same ideas embodied in 

 it are comprised in Prof. Thomas' articles upon the same subject, which are published in 

 this volume, it is omitted here. 



See page 243 of this volume. — Editor. 



