Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Frequency of chromosomal aberrations in two inbred mouse layers (Mus musculus)?. BALB and C57 mice inbred strains were analysed by means of ?in vivo? cytogenetic techniques in order to determins the frequency of chromosoma aberrations not induced by any clastogen. These findings are analysed taking into account that chromosome aberrations play a fundamental rols in the evolution of karyotypes. The knowledge of the phenomena involved in the production of spontaneous macromutations could contribute to the understanding of several cytotaxonomic problems.

Comparative study of the histological structure of the femur of some amphibians?. A similarity between the diafisis? histology and the weight or activity of the species has been found. The basic structure modifications are: Havers Systems? presence and distribution, Laminar Systems? zonification and the increase in concentration of celular spaces. The epiphysis shows an increase cartilage calcification and modification in relation to the diaphysis architecture.

Comparative histological study of the scales and teeth of the shark Squalus sp.?. During dentogenesis, the internal epithelium presents two successive secretory phases with different celular polarity and typology. During the last one, a vitreous substance is laid over the dentine. In scamogenesis the internal epithelium develops during the first secretin phase only.

The nine known species of the genus Hoplopleura Enderlein from Argentine rodents are listed, providing new host records and localities and a key for the identification of the reported species.

Reproductive behavior and feeding data of Agouti paca nelsoni Goldman?. The present study was made in the Sierra de los Tuxtlas, SE of Veracruz, México, in the perennifolia high forest zone. Behaviour studies in the habitat were based on 30 specimens of which 8 were collected.

Notes for a monograph on the Argentine Corixidae (Insecta, Heteroptera)?. The most important features found during the study of Argentine members of this family are presented.

?Observations on Bruchidae (Coleoptera) of Northwestern Argentina, II. Morphological and biological studies of some species of Amblycerinae and Bruchinae? Bionomics and morphological characters of the preimaginal stages of Amblycerus caryoboriformis (Pic) Sennius laminifer (Sharp) and Stator bisbimaculatus (Pic), three species of Bruchidae commonly found in N.W. Argentina are described here. The morphology of the adults of A. caryoboriformis and S. bisbimaculatus is also given. Results are compared with those already known from other species of the same genera and with other groups of the mentioned family.

?Preliminary study of the stomach contents of the common sardine Clupea (Strangomera) bentincki, Norman 1936, Pisces, Clupeidae, in the VIII Region, Chile? Twenty one samples of Clupea (S.) bentincki were collected from the commercial fisheries catch in Chile?s Eighth Region (36°S Lat.) for stomach content analysis. The most abundant food items were identified as the diatom genera Skeletonema, Biddulphia, Coscinodiscus, Nitechta, and the dinoflagellate genera Ceratium and Peridinum.

?Mechanical factors in the reproductive isolation of Thynninae (Hymenoptera, Tiphiidae)? The sequence of premating mechanisms in the reproductive isolation of four species of Thynninae (Elaphroptera scoliaeformis, E. atra, Anodontura tricolor, and Telephoromyia laeta) is studied in this paper. The following barriers are considered for the species involved: habitat isolation, olfactory stimuli and mechanical factors. Olfactory stimuli apparently play a double role as a locating and as an isolating mechanism; visual stimuli are important only to determine the exact position of females at a close range. In both species of Elaphroptera the male performs a very brief antennal tactile exploration of the female body; it was not possible to ascertain the role of this activity either as olfactory or as a mechanical recognition of female posture. The mechanical isolation is accomplished by the mandibular-prosternum grasping mechanism and by some special modifications of male mesosternum in relation to the metasoma of females; these modifications are highly specific and represent one of the most significant barriers in the reproductivo isolation of Thynninae.

?Dilemmatic key for the recognition of the three larval stages of Chrysopa lanata lanata (Banks) (Neurop. Chysopidae)? With the purpose to establish the close relation between different ages of Chrysopa lanata lanata and its preys, a dilemmatic key was constructed and illustrated with drawings, to recognize the three instars larvae. The study is based on the morphological characters used by Tauber (1974) for the systematics of North American chrysopid larval studies. The following elements are considered: lateral and dorsal setiferous tubercles of abdomen, dorsolateral setiferous tubereles of the thorax, number of setae and different colored marks of the head.