This brief concerns the present state of knowledge of the immature stages of Lepidoptera. It is written with three objects in mindéto focus attention on the widespread neglect of serious studies of the immature stages and the weaknesses to be found in projects involving them, to interest in this rugged, highly demanding branch of lepidopterology the few students that may be qualified, and to urge the provision of appropriate positions for which the students can apply.

The first signs of Phytomyza lanati Spencer activity are the feeding marks of the adult on the lower leaf surface of Heracleum lanatum Michx. In Alameda County, Calif., the adults were first seen in January and the larvae were present from mid-February to mid-June. Eggs are laid in the spongy mesophyll and the serpentine mine, made by the solitary larva, is mainly confined to the palisade layer. The larva remains within a single mine until just before puparium formation. At this time the mature larva exits from the leaf through a cut in the lower surface and drops to the soil. At 75 ± 1°F the average duration of the three immature stages are 47, 36, and 60 hours. Because the depth of the mine is constant, the surface area of the mine indicates the relative volume of food consumed. A comparison of the instars shows that the amount and rate of tunnelling increases greatly with each succeeding moult. Under constant temperature there is no significant difference between the amount mined during equivalent light and dark periods.

Adult activity, such as feeding, mating, and oviposition, occurs on the underside of the leaf. Feeding on the plant exudate appears necessary for sustaining adult life.

Three hymenopteran parasites were reared from P. lanati.Biological characteristics served to differentiate P. lanati from other Phytomyza species.

One ounce of ten per cent granular disulfoton, per tree, applied to 3- and 4-year old blue birch in mid-May, was found to take approximately 2 weeks before reaching significantly toxic levels in the leaves. Thereafter, these levels gave excellent control of Fenusa pusilla (Lepeletier) for the 1-year-and-4-month period of the experiment (May 1964 – September 1965). At this dosage, it would appear, the chemical can indefinitely suppress populations of the birch leaf miner if applied once every 2 years.

Construction and performance of a humidity chamber, designed to provide an optimum relationship between volume and conditioning-solution surface area, are described.

Extreme differences in survival of eggs of Ctenicera destructor (Brown) were observed when eggs were placed at depths ranging from 1/2 to 4 in. in the soil in the field. These differences were closely related to the soil moisture variations recorded during different seasons. Eggs that had absorbed water before being placed in the field were much more resistant to desiccation than those that had not absorbed water.

In the laboratory, eggs absorbed water, developed and hatched in soil dried to a constant moisture level of 8.2% (dry weight basis) at 98% R.H., but were unable to absorb water from soil dried to moisture equilibrium at 96.6% R.H., or from soil wetted to moisture equilibrium at 98% R.H. Some water was absorbed by eggs placed in air at 98% R.H., but this was insufficient for normal development and hatching. The soil moisture tension of soil dried to moisture equilibrium at 98% R.H. was calculated as approximately 31 atmospheres. It is evident that eggs are able to develop remarkably high internal suctions in order to absorb water from such soil.

Both the field and laboratory results showed that in drying soil, the lower limit of soil moisture at which eggs could absorb water was about 8%, considerably below the permanent wilting percentage (9.9%) of the soil used in these studies.

The microtopography of a small area of tamarack bog was examined in detail and related to the distribution of cocoons of the larch sawfly Pristiphora erichsonii (Hartig). The relief of the ground surface under tree crowns was very similar to the surface not under crowns, although the whole profile was slightly higher. Cocoons were found down to the limnic peat, corresponding to the level of the lowest depressions, with the greatest numbers per unit area in the hummocks.

The microtopographies in six tamarack bogs were sampled systematically and related to water levels, and an expression combining these two factors was related to larch sawfly survival. The microtopography in each bog did not change appreciably over a period of several years, but differences between bogs were pronounced and had a marked influence on the degree of flooding caused by equal changes in water tables. Excessive moisture during the period 1955–1966 was the prevalent condition in most of the bogs and extreme drought occurred only in 1961. There appeared to be a linear relationship between sawfly survival and an expression rating the favorableness of the cocoon environment in relation to excess moisture, but four divergent observations occurred among the data for 32 plot-years. It was postulated that these divergences were due to high mortality caused by a factor other than excess moisture.

Steremnius carinatus (Boheman), once considered a scavenger, has become recognized as a pest of coniferous seedlings. The weevils breed in roots of fresh stumps and in buried slash on logged areas, and adults emerge by the end of the second summer after logging. Adults girdle young seedlings from near the root collar to 1 in. above ground level, but seldom attack the second year after planting. Adult weevils are long-lived, and can survive three or more winters, establishing broods each spring. They eat a wide variety of vegetation and fruits and other materials containing sugars and starches. Greenhouse trials demonstrated selective feeding on seedlings and field tests showed that the weevils breed in most coastal coniferous species in British Columbia. Rates of brood development ranged from 2 months at 80°F to 24 months in unheated outdoor conditions. Differences in rates of development, apparently related to temperature, were found between localities. Phloem may be suitable for oviposition 2 years after logging, but often is depleted by the feeding of other bark-mining beetles. Although some weevil damage is caused by emergents from stumps on rights-of-way, damage from larger populations emerging later from newly-cut sites may be reduced by planting immediately after cutting.

The following new Pyraustinae from New Guinea are described and figured: Haritala szentivanyi, Aphytoceros hollandiae, Talanga nubilosa and T. iridomelaena.

A survey of poultry ectoparasites was carried out on 90 flocks of various types in Nova Scotia and Prince Edward Island. Eighty-one per cent of the flocks were carrying one or more species of ectoparasite. The chicken mite, Dermanyssus gallinae (DeG.), was present on two out of three flocks and was most frequently located in the joints of the roosts. Chicken lice were parasitizing one out of three flocks. The two most frequently found species were the shaft louse, Menopon gallinae (L.), and the chicken body louse, Menacanthus stramineus (Nitz.). One other species of mite and two other species of lice were also found. About 30% of the flocks were infested with the European chicken flea, Ceratophyllus gallinae (Schr.).

Operators were aware of only 42% of all infestations found on their flocks. They were most likely to be aware of the chicken mite and had recognized 54% of these infestations. In most cases operators could not distinguish among the various species of ectoparasites.

Control measures had been carried out on 57% of the flocks surveyed. Nicotine sulphate, the most popular compound, had been used on one-half of the flocks for which control measures were reported. Organic insecticides had been used on one-third of the treated flocks.

Messa populifoliella (Townsend), long known in the United States but new in Canada, is univoltine and overwinters as a prepupa in the soil beneath the host tree. In New Brunswick the larvae mine the leaves of Populus eugenei Simon-Louis creating blotch mines. The various stages of the sawfly are described and pictured and six parasite species are named.

Survival of the balsam woolly aphid on Abies grandis logs was observed to evaluate the danger of spreading the pest while moving logs. Active stages of the aphid survived submergence in sea water for 7 days and periodic sprinkling with sea water for 3 weeks. Dormant stages survived submergence up to 28 days. Active aphids survived on logs in the forest as long as 5 months. Crawlers frequently re-established on logs and completed a second generation there. Dormant neosistentes on autumn-felled trees persisted over winter and resumed development in the spring. Recommendations for moving infested logs through uninfested areas are made.

The known distribution, biology, and life cycle of the yellow-poplar leaf-mining weevil Odontopus calceatus (Say) are presented. Illustrations of mature larva, larval head capsule, and pupa, and the damage to the leaves of yellow poplar, are given.

The pine cone willow gall midge is univoltine in Michigan. Adults emerge from the galls on Salix eriocephala Michx. and other willows on warm days in late April or early May. Eggs are laid singly on the leaves and stems of the host. Head capsule measurements indicate three larval instars. The first-instar larva emerges in early May and penetrates the soft tissues at the base of the developing shoot tip. Shortly thereafter, the gall begins to develop and is about half grown by the time the second-instar larva appears in late May. The last-instar larva appears in July. Before overwintering, the larva constructs a cocoon which may or may not be closed at the top. Pupation occurs in early April. Numerous inquilines and parasites inhabit the developing and mature gall.

The pupal stage of the pales weevil, Hylobius pales (Herbst), is described with notes on distinguishing it from the pupa of Pachylobius picivorus Germar, together with a means for sexing pales weevil pupae.

Monellia californica Essig is redescribed and transferred to Monelliopsis Richards. A key to the known species of Monelliopsis is offered and a lectotype established for californica.

The following new species of Apilocrocis Amsel are described: A. novateutonialis, Brazil and Bolivia; A. yucatanalis, Mexico; A. pseudocephalis, Mexico; A. steinbachi, Bolivia. The following species are transferred to Apilocrocis from Syllepte Hübner: S. excelsalis Schaus, S. glaucosia Hampson, S. albicupralis Hampson = S. mitanalis Schaus, new synonymy, S. cephalis (Walker) = Pilocrocis microbathra Meyrick, new synonymy, S. albipunctalis Hampson, S. brumalis Barnes and McDunnough, S. pimalis Barnes and Benjamin. A key to these 11 species is given.