A research programme in New Brunswick coordinating the use of radar, specially-instrumented aircraft, and observations from platforms extending above the forest canopy has established the massive scale and regularity of evening take-off flights by spruce budworm moths, Choristoneura fumiferana, and of subsequent nocturnal dispersal at levels high above the ground. A night-viewing telescope showed moths taking off from the tree crowns up until 2330 h, 2.5 h after sunset, while radar dot echoes of uniform strength and size began to appear each night at about the same time. Direct identification of radar echoes was provided by simultaneous catches of budworm moths taken in insect-collecting nets on Cessna 185 aircraft. Moths collected during emigration, displacement, and immigration contained a high proportion of egg-carrying females.Radar recorded the rates of climb and the altitudes reached by the flying moths and provided extensive data on their numbers, density, orientation, direction, speed, and duration of displacement. Airborne moths became concentrated in zones of wind convergence, and line-echoes from moths at wind-shift fronts were detected on radar at distances of 30 km. The time of passage of wind-shift fronts over a surface site was detectable by pilot-balloon observations and by sensing equipment on a 24-m meteorological tower. Wind-fields over New Brunswick, as found from a DC-3, showed a marked contrast between the high degree of wind uniformity on many evenings and convergent winds on other evenings. Attention is focussed on the potential effects of meso-scale sea breeze fronts, of which one example is presented, and of storm cells on moth concentration and dispersal.Through the use of radar, spruce-budworm moth dispersal has been viewed for the first time in its entirety and the integrated research programme has provided new data for better evaluation of the significance of moth dispersal in the initiation and spread of infestations.

New Brunswick outbreaks of the spruce budworm which began in 1912 and 1949 are considered in relation to the theory of climatic release. Studies OII a natural population show that larval developmel~t is more rapid in dry and sunny weather than in hulllid and cloudy weather. Polar air masses bring the favorable conditions, and tropical air masses and cyclones the unfavorable. June precipitation and temperature records, analyzed in conjunction with weather maps, show that climatic changes took place in regions where the outbreaks developed. The outbreaks were preceded by dry and sunny summers d~rring four or five consecutive years. Although direct mortality of the budworm due t o adverse weather co~lditions has not been observed, favorable climatic conditions may have indirectly promoted pop~llation increase from the endemic t o the outbreak level in the following ways. Flower production became more frequent in periods of dry years and larvae which fed on staminate flowers developed more rapidly. Larvae that developed early in the season gave rise to more fecund females than larvae that developed late. The age of current foliage consumed is also related to fecundity. The rate of development of balsam lir relative to the budworm varies from year to year. I t is postulated that the average fecundity of the budworm increases in the pre-outbreak years as the result of favorable climatic conditions and greater than usual flower production. Larval mortality is greater in years with a prolonged developmental period although the increase is not statistically significant. The theory that outbreaks in New Brunswick resulted from the spread of populations from outbreak areas to the west will be co~lsidered in the second part of this two-part paper. liManzlscript

In Part I of this papcr consideration was given to the role of c!imate in the initiation of outbreaks of the spruce budworm in New Brunsv~ick. Analysis of the avai!able \\;eather data sho\\:ed that the 1912 and 1949 outbreaks developed after several consec~rtive dry summcrs. Support was given to thc theory of climatic release, which csplains thc time and place of outbreaks 011 n climatic basis. Howevcr, the recorcletl history of the sprucc bucl\\rorm also sho\vs that high populations appeared ill New Brunswick shortly after "sprcading" through Quebec, and this suggests that the New Bruns\vick outbreaks are also a continuation of this spread. I n the prcserlt part of the paper coi~sideration is given to the role of dispersal. ;\loth dispersal is a morc effective agent of spread than larval clispersal. 5 1 0 t h~ may be transportetl by convectional and turbulent air currents for l o n~ dista~lces. Light traps uscd to detcct the incidence of moth mo\:ernents, sho\\;ccl that large segments of a pop~rlation may bc transfcrrecl frorn onc area to another. Unspent fenlales often pretlominate in thcse no\-cments. hloth invasion \\;as not detected bcforc the 1949 outbreak although thcre is e\:iclence fro111 other sources that it occurrecl in 1948. \\'hen deposited in dense, mature, softwoocl stancls, the moths can crcate outbreaks, but \\-hen deposited in young, opcn, or mised-\\rood stancls thc ensuing high populations so011 dcclinc unlcss I,olstcretl by repeated invasions. Populations i11 Ncw Bruns\\~icl; sho\\;cd gradual and general increases as early as 1917. I t is thought probable that these increases rcsultccl from thc I~uilcl-up of local populations through clirnatic relcase. The nearest highly-populated celitel-s were over 100 rnilcs to the \\:est in 1947. Latcr, in\.asio11 of moths from centers outside of the I~'ro\.i~~cc nla!-have hastcnecl the proccss.

Can. Ent. 102: 546578 (1970) The balsam woolly aphid was introduced over 60 years ago from Europe into the Maritime Provinces of Canada where it established on Abies balramea (L.)Alill. Ecological characteristics of the insect that are important to the survival and spread of populations in the new environment are feeding habits, cold-hardiness, and dispersal capacity. The aphid feeds on the bark cortex of all parts of the tree from the stem to the crown. 'Stem attack' refers to the population established on the main stem while 'twig attack' refers to the population established in the crown where the aphid may settle on numerous sites but mainly at the base of young shoots. Freezing is fatal and the probability of freezing increases as temperatures fall below -5°F. There are no survivors at -35°F no matter how LC climat des illaritimes rarie de continental i maririme se'on que I'on s'bloigne ou pas des c6tes. Dans chacune des deux rdg.ions. I'infestation a son propre rype, tandis que dans la zone cte transition, elle a un comportenlent 1rr6plier. Dans la &$on maritime, le climat n'influe pas sur Icf tendances de la population. Ainsi la prohabidit& que la tempiraturc hibernale baisse en bas de -15°F' n'Ctant que de 0.10, les Pucerons sun-ivent hien sur la tige et dam Ia cime dans laqucile ils sont dispersks et qu'il~ endommapent dans routes ses parties. En region continentale. par contre. la probabilitb que la tcmp6rature baisse i -30°F est de 0.46 et lcs survirants sc rencontrent seulement i la base de I'arbre dans la neige. Sous la voi'ite foliacte, la faible vitesse du vent rkduit I'Ctendue et la propagation des infestations et le taux de dommaae aux tipes demeure bas. Dans la zone de transition, les hivers sont parfois doux, parfois tr&s rigoureux; la mortalitt des arbres attaquts s'Cl&ve beaucoup dans certains peuplements alors que dans les peuplements adjacents et aussi vulnkrables, I'infestation s'arrkte h cause du froid intense qui y s h i t . Volume 102 THE CANADIAN ENTOMOLOGISTAbstract Can. Ent. 102: 578-585 (1970) Poecilips pteridophytae Schedl is the firm species of Scolytidae to be found on a fern. It appears to be fairly widely distributed in New Guinea on the tropical bracken fern, Ptericiirnn aqrtilinrtm (L.). The association is most probably of recent el-olutionary origin. T h e immature stafres are described in the text. Its life history is relatively short, the life cycle taking 2 to 4 months, and takes place wholly within the stem of the fern. except for emigrating adults. P. pteridopl~ytae rnay hare comiderable economic potential as a biological control agent of hrncken fern in countries where it is a pest.

The assumption that the number of eggs laid by a spruce budworm moth in the field is the same as the number laid under laboratory conditions is shown to be false. A method is described for estimating what proportion of the potential fecundity obtained in the laboratory is actually laid in the field. The proportion was shown to range from 0 to 1 for individual females, but averaged between 0.70 and 0.86 for a given population at one locality. Results of this investigation have implications in population dynamics studies of the spruce budworm.