21 



aud the number of trees of each kind planted, as well as the number 

 alive at the end of the season, is stated. 



BULLETIN NO. 13, APRIL, 1889. 



Insects and insecticides, I. H. Orcutt, M. D., Pii. D. (pp. 3-2S). — 

 This contains practical directions for the catching, preserving-, and 

 transportation of insects, aud for the use of insecticides ; an illustrated 

 account of spraying apparatus; and compiled notes on the following 

 insects: Cecropia emperor moth {Platysamla cecrojjm, Linn.), American 

 silk-worm (Telea polypheynus^ Linn.), sphinx moths {^phitigidce)^ elm 

 saw-fl^' [Cinibex americana, Leach), yellow-spotted willow-slug {Nematus 

 veniralis. Say), streaked cotton wood leaf-beetle {Plagiodera scripta, 

 Fabr.), cut-worms, southern cabbage butterfly [Pieris protodice, Boisd.), 

 imported cabbage butterfly {Pieris rapce, Schrank), cabbage plusia 

 (Plusia ftrassicfc, Riley), zebra cabbage- worm (Ceramica j9Jcto, Harris)^ 

 cabbage plant-louse {Aphis hrassica', Linn.), Colorado i)otato beetle 

 {Doryplwra deccmUneata, Say), and striped cucumber beetle {Diabrotica 

 vittata). — The following items are of special interest: 



Cecropia emperor worm. — These worms were fonml .it this Station dnriug the past 

 eummer destroying the box-elder, maple, willow, cottonwood, plum, apple, cherry, 

 mountain ash, elm, catalpa, etc. » * * The destruction has been so great in 

 many places it is feared that tree-raising mtist be abandoned if something is not done 

 to check them. If the cocoons are collected in a given locality there will be no 

 worms the following season. The cocoons maybe torn down from the tops of the 

 larger trees with a hook fastened to a pole. By opening a number of cocoons aud 

 carefully comparing the weight of those containing healthy pupte with those which 

 do not, it is not difficult to assort them. Only those conla'ming healthy pupw should 

 be destroyed, as many of the others contain the pupce of one of the cecropia's greatest 

 enemies and the farmers' faitliful friends. Cocoons may be kept in boxes (on shelves 

 if many are to be preserved) with one-half inch holes bored in them. The holes will 

 not allow mice to enter, but will allow small insects to escape. If the cocoons have 

 not been assorted moths will .appear about the first of June, which may be taken out 

 and destroyed. The friendly insects may not appear until several weeks after the 

 moths have been destroyed. If the cocoons are. carefully gathered .and cared for, 

 as stated above, the relative number of the parasitic insects to the number of cecropia 

 larva) will be greatly increased, as few cocoons need be overlooked in gathering. 

 This will enable the small insect friends to almost annihilate the large enemies. If 

 the worms .are not numerous they may be picked off and destroyed. One man imles 

 that he cut about twelve thousand in two with shears last summer. They may be destroyed, 

 without being handled, by pouring <a few drops of kerosene along the back from a 

 can with a very small nozzle. If the trees are large they can be fastened to a long 

 pole at an angle, and bo used by a person standing some dist.ance from the tree. If 

 but few trees are to be protected, this seems to be by far the better way to proceed. 

 Use but a few droi)s of kerosene on each worm, as it will kill the leaves if jioured on 

 them. 



Elm saw-fly. — These saw-flies are frequently regarded as " big hornets" bj^ careless 

 observers. The abdomen of the male varies in color from brick-red to shiny black, 

 while the abdomen of the female is plainly marked along each side with white. 

 These insects appear the last of May or first of June, and begin at once their work of 

 destruction upon the willow, soft maple, etc. They are provided with very powerful 

 jaws for cutting slits in the bark, and with loiig tongues for lapping up the sap. One 



