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Intragastric water prevented the acquisition of schedule-induced polydipsia by rats despite its lack of effect on established polydipsia. When drinking was maintained (by the prior induction of dry-mouth drinking) schedule-induced polydipsia was acquired in spite of intragastric hydration. The results suggest that polydipsia is an acquired, operant, behavior rather than an exaggeration of an existing behavior.

The embryonic development of intestinal lymphoid tissue and immunoglobulin-containing cells (µ-, γ- and light chain determinants) was examined in 55 porcine fetuses. Lymphoid cells in a characteristic follicular distribution were found in Peyer's patches as early as 50 days of gestation, but detection of Peyer's patches from 50 to beyond 70 days of gestation required microscopic examination of serial sections of the intestines. The size of the intestinal lymphoid follicles steadily increased during gestation, but cortico-medullary division was not observed until after birth. IgM-containing cells were first seen in 55-day spleens and were followed by IgG-containing cells in the thymus 10 to 15 days later. These observations are interpreted as support for the hypothesis that the lymphoid follicles in Peyer's patches are mammalian bursa-equivalent sites.

Diagnostic studies on the progenies of mosquitoes reared from infected eggs collected in the field confirmed earlier evidence that transovarian transmission of Thelohania (Microsporidia) occurs commonly and may account for levels of infection observed in certain populations of mosquitoes. In some species of mosquitoes, however, peroral transmission is a prerequisite for transovarian transmission.

This invention relates to a process for producing aromatic nitriles, and is more particularly concerned with a catalytic process for producing aromatic nitriles from aromatic hydrocarbons. Aromatic nitriles are organic compounds containing combined nitrogen. Their formula may be represented...

The three known species of Saldoida are described and figured, their habitats and habits are discussed, and techniques are given for collecting these very agile shore bugs. S. slossonae Osborn ( = S. slossoni Osb.) ranges in the coastal states from New Jersey to Florida and Texas, S. cornuta Osb. from Florida to Mississippi, while the Oriental S. armata Horvath is known from Taiwan (Formosa), the Phillippines, and India. Subfamily status as Saldoidinae Reuter is recognized for these species.

1. The CO2 absorption method of measuring apparent photosynthesis was found to be well adapted to use with potato leaves. The major problems encountered were the accurate measurement of air volume in each unit and the prevention of excessive temperature build-up in the leaf chambers. 2. The general level of CO2 absorption by potato leaves was increased following effective rains. 3. Wilting of leaves caused a decrease in the rate of CO2 absorption. 4. Maximum assimilation rates of Triumph leaves were found between the temperatures of 80 and 90° F. under field conditions. 5. Highest assimilation rates were usually recorded between 8:00 and 10:00 a.m., followed by a gradual decline throughout the remainder of the day. 6. Large natural variations in rate of CO2 absorption were found with paired leaves on the same and different potato plants. 7. Leaves located near the base of potato plants were found to absorb CO2 only two-thirds as rapidly as the 3rd or 4th leaves below the terminal leaf cluster. 8. In comparable tests with four varieties, Triumph had the lowest rate of CO2 absorption per unit area of leaf surface.

A study initiated in New Jersey in 1955 showed a total of 53 species of insects found in and around stored-grain structures and included 36 species of Coleoptera, 5 species of Lepidoptera, 1 species of Psocoptera, 9 species of parasitic Hymenoptera, and 2 species of predacious Heteroptera. Twenty-eight bins were treated at harvest in 1956 with pyrethrins emulsion at 1.0, 1.5, and 2.0 p.p.m., a pyrethrins dust at 1.5 p.p.m., malathion emulsion at 25.0 p.p.m., and malathion dust at 5.0 p.p.m. The most effective treatments were the pyrethrins dust and the malathion dust and emulsion. Twenty-one bins were treated at harvest in 1957 with a pyrethrins emulsion at 1.5 and 2.0 p.p.m., a pyrethrins dust at. 1.5 p.p.m., and malathion dust at 5.0 p.p.m. A fumigant containing 3.5% ethylene dibromide, 10.0% ethylene dichloride, 10.0% carbon bisulphide, and 76.5% carbon tetrachloride was applied to seven bins 6 weeks after harvest. The latter treatment, plus malathion dust and the highest dosage of the pyrethrins emulsion, provided the most effective protection against insects. Species such as the foreign grain beetle ( Ahasverus advena Waltl) and a hairy fungus beetle (Typhaea stercorea (L.)) were abundant only in 1956 when the grain had an average moisture content of 14.0% at initial storage. The saw-toothed grain beetle (Oryzaephilus surinamensis (L.)) and the rusty grain beetle (Laemophloeus ferrugineus (Steph.)), especially the former, were abundant both years. The Angoumois grain moth (Sitotroga cerealella (Oliv.)) was observed infesting wheat, corn, rye, and barley in the field. The fumigant mixture applied at the manufacturer's recommendations, was also very effective in reducing heavy insect infestations in 10 bins of wheat in the fall of 1956.

The regular mosquito iridescent virus and a blue MIV of Aedes taeniorhynchus were serially passed through 68 and 30 generations, respectively, of larvae of A. taeniorhynchus ; the average rate of infection for the regular MIV was 16%; that for the blue MIV was 21%. The maximum level of infection was usually reached when large numbers of early-instar larvae were exposed for 48 hr to substantial amounts of MIV material and the larvae were reared to the fourth stadium at 25°C. The rate of cross infection between known hosts of MIV was always less than 1%. Attempts to transmit MIV to larvae of nine species of mosquitoes not known to be hosts of MIV were successful only with Aedes sollicitans . About a 20% patent infection occurred in the larval progeny of adult A. taeniorhynchus derived from early fourth-instar larvae exposed to MIV. Such transovarian transmission was also observed in the MIV of Psorophora ferox .

Evidence is presented which strongly suggests that cholinergic mechanisms are not the exclusive mediators of thirst. Atropine sulfate, delivered systemically, in doses known to eliminate carbachol-induced drinking, did not affect or only partially suppressed drinking induced by: (1) water deprivation; (2) systemic or intracranial cellular dehydration; (3) isosmotic intravascular depletion; (4) systemic injections of renin; or, (5) intracranial injections of angiotensin. It had no effect on the prandial drinking of desalivate rats. Furthermore, bilateral intracranial injections of atropine sulfate in the lateral preoptic or lateral hypothalamic areas exerted only a mild inhibition on the drinking caused by systemic injections of renin, and none at all on drinking following systemic cellular dehydration. The partial contribution of cholinergic mechanisms to thirst makes plausible the findings that drinking caused by cholinergic stimulation differs from that following water deprivation.

Parasites of the genus Thelohania were studied in 13 species of mosquitoes collected from two parishes in southwestern Louisiana. New host records were established for Aedes grossbecki, A. sollicitans, A. sticticus, A. taeniorhynchus, Culex salinarius, Psorophora confinnis , and Anopheles bradleyi . The host-parasite relationships of the mosquitoes and associated Thelohania were classified into four types.

A scanning electron microscope was used to study the sporangia of at least 6 species of Coelomomyces from 9 species of mosquitoes. The scanning micrographs obtained of (1) Coelomomyces punctatus from Anopheles quadrimaculatus , (2) C. dodgei from A. crucians , (3) C. quadrangulatus from A. crucians , (4) C. macleayae from Aedes triseriatus , (5) C. pentangulatus from Culex erraticus , (6) C. sp., probably pentangulatus , from Culex peccator , (7) C. psorophorae from Psorophora howardii , (8) C. near psorophorae from Culiseta inornata , (9) from Aedes sollicitans , and (10) from Aedes taeniorhynchus showed morphological differences in the surface microstructure of the sporangia of most species.

The incidence of Coelomomyces punctatus and C. dodgei was studied in larval populations of Anopheles crucians in two ponds (Chloe 3 and Chloe TNT) in southwestern Louisiana for 4 1 4 and 2 1 4 years, respectively. The annual level of infection of C. punctatus in Chloe 3 decreased progressively each year from a high of 67% in 1966 to a low of 12% in 1970; about one-third of all larvae collected from this pond were infected. In Chloe TNT, the level of infection of C. dodgei was lowest in 1968 (24%) and increased each year to a high of 59% in 1970; almost half the larvae collected were infected. In Chloe TNT, the highest average monthly levels of infection occurred in January and September, and the highest occurred in Chloe 3 in January, March, and October. In Chloe TNT which dried only one time, no relationship was seen between levels of infection and temperature. Also in this pond, the incidence of parasitism generally increased as the larval populations increased although this difference was not significant. The persistence of C. punctatus was especially apparent since it appeared in larval populations after an absence of 29 wks caused principally by lack of water.

The morphology and development cycle of the microsporidian Plistophora caecorum sp. n. are described. The parasite invades the gastric caeca of the mosquito Culiseta inornata and is transmitted transovarially. Laboratory and field observations of host-parasite relationships are presented.

The fungus Coelomomyces macleayae has been reported from treehole mosquito larvae of three Aedes subgenera in Australia, Fiji, and the United States. This fungus is now recorded for the first time from a mosquito of the genus Toxorhynchites, the large predatory larvae of which are of some importance in the naturalistic control of associated mosquito pests and vectors. A single parasitized larva of T. rutilus septentrionalis was collected from a magnolia treehole (previously used for A. triseriatus infection experiments) near West Lake, Louisiana, in September, 1971. Larval A. triseriatus and Orthopodomyia signifera were also present but were uninfected.