Provas cruciais da dicentricidade dos cromossômios dos hemipteros

Studying the meiosis of two Hemiptera, mamely, Lybindus dichrous (Coreidae) and Euryophthalmus humilis (Pyrrhocoridae), the author has found new proofs in favor of the existence of a centromere at each end of the chromosomes of the insects belonging to that order. Following the behaviour of a pair of large autosomes of Lybindus, he was able to verify that in the first division of the spermatocytes, the tetrad they form divides transversely by the middle, giving rise to two V-shaped anaphase chromosomes that go to the poles with the vertex pointing forwardly. From the end of the first division till the metaphase of the second one, the centromeres occupying the vertex of the V go apart from one another, making the chiasmata existing there slip to the opposite extremities, what changes the V into an X. When the chiasmata reach the acentric ends, the X is again converted into a V. The V of the secondary metaphase, therefore, differs from the V of the primary anaphase, in being inverted that is, in having the centromeres in the extremity of its arms, and no longer in the vertex as in the latter. The opening out of the chromosomes starting at the centric extremities in order to recuperate the dumbbell shape they show in the secondary anaphase, just in the manner postulated by PIZA, is thus demonstrated. In Euryophthalmus humilis it was verified once more, that the heterochromosome, in the secondary spermatocytes, orients parallelly to the spindle axis, accompanying with its ends the anaphase plates as they move to the poles. The author is in disagreement with NORONHA-WAGNER & DUARTE DE CASTRO's interpretation of the behaviour of the chromosomes in meiosis of Luzula nemorosa.

Nota sôbre Fulgora

This paper includes a few notes on some Homoptera insects of the genus Fulgora, according to a study carried out on a little collection belonging to the Laboratory of Zoology of the Escola Superior de Agricultura "Luiz de Queiroz" (Piracicaba, Brazil). The following species are mentioned: F. servillei Spinola, F. lucifera Germar, F. orthocephala (Pinto da Fonseca) and F. cearensis (Pinto da Fonseca). The types of the latter having been collected in Fortaleza (Ceará), its area of distribution is considerably enlarged by the information of its occurrence in the State of São Paulo.

The Canadian entomologist.

v. 31 (1899)

The Canadian entomologist.

v. 48 (1916)

The Canadian entomologist.

v. 23 (1891)

The Canadian entomologist.

v. 24 (1892)

The Canadian entomologist.

v. 34 (1902)

Os insetos como agentes polinizadores da mangueira

The authors study the insect population that visit the mango trees and search for their pollinizing activity. Prior operations showed that very few bees (Apis mellifera) visited the flowers of mango trees. It was known that the percentage of fecundation is low (Simão 1955), Popenoe (1929), Spencer and Kennard (1955), Lynch and Mustard (1955), Ruehle and Ledin (1955), so that the authors wented to Know if insects could be responsible for this. Insects were collected from mango trees, belonging to 10 orders, which, on the whole are not pollinizing agents. Bees were not collected, 21% were Hymenoptera, 20% were Diptera, 13% Hemiptera, 10% Coleoptera, 3% Blattariae and smoller percentages belonged to other orders.

Contribuição para o conhecimento da Mimosicerya hempeli (Cockerell, 1899) (Homoptera. Margarodidae) e de seu predador Exoplectra erythrogasfer Mulsant, 1851 (Coleoptera, Coccinellidae)

This paper deals with Mimosicerya hempeli (Cock., 1899) (Homoptera, Margarodidae) and its predator, the ladybeetle Exo-plectra erythrogaster Muls., 1851 (Coleoptews, Coccinellidae), which were found to occur at Piracicaba, State of São Paulo, Brasil. The first is a pest of "cássia imperial" (Cassia fistula L.), and several other trees. As those insects are little known, a few bionomical notes and descriptions of some of their stages are presented. The adult scales proved to be very resistant to an application of mineral oil plus malathion. Methyl Demeton applied with irrigation water showed no control. The same insecticide injected into the trunk gave very poor results.

Entomological news, and proceedings of the Entomological Section of the Academy of Natural Sciences of Philadelphia.

v. 15 (1903)

Entomological news, and proceedings of the Entomological Section of the Academy of Natural Sciences of Philadelphia.

v. 30 (1919)

Entomological news, and proceedings of the Entomological Section of the Academy of Natural Sciences of Philadelphia.

v. 3-4 (1892-1893)

Entomological news, and proceedings of the Entomological Section of the Academy of Natural Sciences of Philadelphia.

v. 23 (1912)