INSECTS INJURIOUS TO HOUSE PLANTS, ETC. 501 



If auj' of us should think to try any of the above mixtures, Ave should pro- 

 ceed with the greatest caution, experimenting on each variety of plants on a 

 small scale at first, that we may rightly gauge the mixture to the endurance 

 of the various plpnts. 



Thrtps. — Tfu'ips adonidum — {Suh-order Hemiptera — Family Thripidm) : 

 The thrips would be classed among the worst insects of the conservatory in the 

 old country. They are also very troublesome, in the older parts of our own 

 country, — around Detroit, here at Adrian, and in our southern counties they 

 are likewise a serious pest. These lice-like insects maybe known by their pos- 

 sessing long narrow fringed wings. They differ in color, the larvae and pupa3 

 being yellowish white, while the imago is black, with dirty white wings. 

 They are especially destructive to azaleas, vines, ferns, dahlias, phloxes, and 

 verbenas. 



These insects are destroyed by the same means that prove effectual in killing 

 the aphides and red-spiders. What we have already said as to fumigation, and 

 the use of tobacco water, in destroying the plant lice, will also apply in the 

 destruction of the thrips. 



EosE Slug. — Selandria rosae Ilarr — {Family Tentliredinidae — Sub-order Hy- 

 menoptera). — I presume that there are but very few of my hearers but have an 

 acquaintance with these terrible destroyers of our most admired shrub. These 

 insects are to be doubly dreaded, for though they f\iil to ruin, they so disfigure 

 our rose bushes, that they become anything but a joy forever. 



Early in June, the little, back, four-winged fly may be seen around the rose 

 bushes, and on darksome days, may be easily captured. 



These selandria belong to that curious family of Hymenopterous insects 

 called saw-flies, so named from the fact that they possess a most wonderful 

 saw-like instrument, by means of which they form grooves in leaves or twigs, 

 in which they deposit their eggs. 



The rose saw-fly deposits her eggs on the under side of the leaves. These 

 hatch into light greenish larva, yellowish beneath. The larva of the saw-flies 

 possess from eighteen to twenty-two legs, the rose-slugs having twenty-two. 



When full grown, these larva are worm form, and about three-fourths of an 

 inch in length. They eat the parenchyma of the leaves, leaving them sear 

 and withered upon the bush. Having attained their full growth about the 

 middle of July, they descend from the plant, go into the ground, where they 

 form a cocoon, in which they pupate. The larva of saw-flies are usually 

 slimy, hence the name slugs. The larva of the rose saw-fly is not slimy. The 

 insects of this genus, and family too, are frequently two-brooded, as with the 

 pear tree selandria, described in the report of 1872 ; but the rose slug, with us 

 at least in Lansing, seems single brooded. So they remain in the ground as 

 pup^ during the greater part of the year, — from August to May or June. 



Remedies. — Whale oil soap, in solution, is a safe and sure remedy for the 

 evils of the rose slug, but from its disagreeable odor, it is not pleasant to have 

 about. A very weak solution of carbolic acid is also a sure preventive, and 

 is more pleasant to use than the soap solution. White hellebore, either in 

 powder or solution, is death to the destructive currant slugs, and would doubt- 

 less be effectual in destroying the rose-slug. 



The rose-chafer, described in the report of 1872, is, in the beetle state, very 

 destructive to the foliage of the rose bushes, as well as to the grape vines. As 

 stated then, hand-pickmg is a sure remedy against the destruction of these 

 beetles ; as then stated, I have little doubt but sprinkling with Paris green 

 would also destroy the beetles. 



