397 



Megohrkim edivardsi, Lee, found on oak and live oak ; Holopleiira 

 helena, Lee. {marginata, Lee.) bred from laurel ; Rosalia funebris, 

 Mots., breeding in laurel and ash ; Tragidion annulatum, Lee, found 

 on mesquite ; Cyllene antennatus, White, breeding in mesquite ; 

 Clytus phnifrons, Lee, bred from dead branches of wallow ; 

 Xylotreclms undidatns, Say, breeding in Pseudotsuga taxifolia and 

 probably other coniferous trees including Pmus fotiderosa ; X. insignis 

 Lee. {obliieratus, Lee), breeding in various species of willow ; 

 X. annosus, Say, breeding in poplar ; Neoclytus conjunctus, Lee, 

 breeding in Quercus douglasi and Fraxinus oregona ; Atimia dorsalis, 

 Lee, breeding in post cedar ; Desmocerus auripennis, Chevr., 

 D. cribripennis, Horn, and D. californicus, Horn, breeding in elder- 

 berry ; Necydalis laevicollis, Lee, bred from tan-bark oak ; Pyrotrichus 

 ■vitticollis, Lee, breeding in the heart- wood of alders ; Leptalia nmcilenla, 

 Mann., breeding in willow ; Rhagium lineatum, Oliv., breeding in 

 various pines ; Centrodera tievadica, Lee, breeding in Pinus ponderosa ; 

 Pachyta liUirata, Kirby, breeding in fir ; and P. spurca, Lee, breeding 

 in Pseudotsiiga taxifolia. 



Ohapais (J. C). Notes concernant L' "Hemerocampa marquee de 

 Blanc." [Notes on the White-marked Tussock Moth.] — Nat. 

 Ganad., Quebec, xliv, no. 11, May 1918, pp. 163-166, 4 figs. 

 [Received 18th July 1918.] 



In 1917, the orchards of eastern parts of the province of Quebec 

 were severely damaged with the white-marked tussock moth [Hemero- 

 campa leucostigma]. The remedial measures recommended are the 

 collection of the cocoons and the spraying of larvae hatching in May 

 and June. All the cocoons collected should be kept till the following 

 spring in boxes covered with metallic gauze, to preserve any parasites 

 with which thev mav have been infested. 



Moore (W.) & Graham (S. A.). Physical Properties governing the 

 EfTicacy of Contact Insecticides.— J?. Agric. Research, Washington, 

 B.C., xiii, no. 11, 10th June 1918, pp. 523-538. 



Formerly it was considered that contact insecticides killed the 

 insects to which they were applied by means of their vapour and that 

 their volatility was the index of their toxicity when used as spravs. 

 In working with insect eggs, however, it was found that materials 

 not volatile enough to kill insects or their eggs by their vapour within 

 a reasonable length of time were among the most effective materials 

 when applied to eggs as liquids. 



This action is due to the physical properties of wetting and spreading, 

 terms that are not strictly synonymous, wetting being the adhesion 

 between the liquid and the solid, while spreading is the excess of the 

 adhesion between the liquid and solid over the cohesion of the liquid. 

 If the cohesion of a liquid is less than the adhesion between the chitin 

 forming the outer covering of the insect and the spray, then the liquid 

 will spread, the rate at which this takes place being governed by 

 the viscosity of the liquid. If the cohesion of the liquid is greater 



