Jan.'] HOT-HOUSE INSECTS, &c. 141 



scarcely to be perceptible to the naked eye. They gene- 

 rally lurk close to the veins of the leaves of plants, and 

 frequently attack esculents. When viewed through a 

 glass, they are seen, when touched, to skip with great agi- 

 lity. The larva is of a high brown or reddish colour. The 

 thrip has four wings, and walks with its body turned up- 

 ward. It frequently attacks the extremities of tender shoots 

 or young leaves, which become shriveled, brown, and will 

 rub to dust easily between the thumb and f]nger. When 

 any leaves or shoots are perceived to be so, if you do not 

 observe the green fly, expect the thrips. They may be 

 destroyed by a fumigation of tobacco, in the same manner 

 as the green fly. By the simple and expeditious method 

 of fumigation, these insects and several others may be de- 

 stroyed effectually at any time they appear. 



Cocus hesperidv.s, or mealy bug, has appeared in the 

 hot-houses about Philadelphia within these few years, and, 

 if not instantly destroyed, increases rapidly. It is of a 

 white dusty colour ; when broken, of a brownish red, gene- 

 rally covered with down, under which it deposits its eggs ; 

 and they, in a few months, come forth in great numbers. 

 The cocus generally is of a dormant nature, but in warm 

 weather they may be seen moving rapidly up the stems of 

 the plants. Fumigating has no observable effect on these 

 insects ; therefore, as soon as they appear, recourse must 

 be had to other means. The liquid made from the follow- 

 ing receipt is death to any of the Cocus tribe : Take two 

 pounds of strong soap, one pound of flour of sulphur, one 

 pound of leaf tobacco, one and a half ounce of nux vomica, 

 with a tablespoonful of turpentine, which boil in four gal- 

 lons of river water to three; then set aside to cool. When 

 boiling, stir it well with a stick, continuing to do so until 

 it is reduced as above. In this liquor immerse the whole 

 plant, drawing it to and fro gently, that the liquor may 

 penetrate everywhere. This done, lay the plant on its 

 side, until it begins to dry, then syringe well with clean 

 water, and put it in its respective station. Where a col- 

 lection of plants is free from any insects of the kind, every 

 plant that is introduced ought to be minutely scrutinized, 

 that the unclean may be kept from the clean : the above 

 insect will feed almost on any plant, but indulges on Crds- 



