ON THE EARLY STAGES OF THE DIPTEROUS FLY, CHRYSOPILA FOLDA, Loew

1883 ◽  
Vol 15 (6) ◽  
pp. 112-113
Author(s):  
D. W. Coquillett
Keyword(s):  
Anterior Part ◽  
Line Length ◽  
Early Stages ◽  
Yellowish White

Larva.—Body polished, yellowish white, nearly cylindrical, anterior part tapers to the head; eleven visible segments; footless; posterior end of last segment deeply notched horizontally and less deeply so vertically; on each side a small notch above sinus of horizontal notch; on under side of each of the two lobes, formed by the horizontal and vertical notches, is an elliptical, reddish-brown raised spot; on under side of last segment, near the anterior end is a somewhat conical impressed spot, the base of the cone being at the anterior end of the segment; in the middle of this cone is a longitudinal impressed line; length from 20 to 25 mm.

scholarly journals Metamorphosis of whitemouth croaker Micropogonias furnieri (Pisces, Sciaenidae)

2020 ◽  
Vol 33 (2) ◽  
pp. 163-182
Author(s):  
Mara Braverman ◽  
Daniel Brown ◽  
E. Marcelo Acha
Keyword(s):  
Developmental Stages ◽  
Anterior Part ◽  
Feeding Activity ◽  
Principal Component ◽  
Morphological Characters ◽  
The Body ◽  
Juvenile Period ◽  
Meristic Characters ◽  
Early Stages ◽  
Micropogonias Furnieri

Fish metamorphosis is an important ontogenetic process with a key role on early stages survival and on successful recruitment to adult populations. The whitemouth croaker (Micropogonias furnieri) is an important commercial resource for the coastal fisheries of Argentina and Uruguay. Metamorphosis, using morphometric and morphological analyses during larval development was studied. Changes in morpho-meristic characters before and after metamorphosis were employed to determine the length interval of this transition by employing Principal Component Analysis. Individuals (n=430) from 4 to 41 mm standard length (SL) were collected in the Río de la Plata estuary (35.45º S, 56.35º W) in March 2006. Length ranges of individual´s developmental stages were associated with the presence of key morphological characters. During early life stages, M. furnieri changes from a big-headed, robust shape larva to a slender and more elongated body form. Most of the morphometric variables showed an inflexion point at 15.2 mm SL, with a 95% confidence interval of 14.0 – 16.4 mm. The anterior part of the body grows faster during early stages, probably related to an intense feeding activity strategy. The completion of pectoral fin rays and the onset of squamation determine the beginning of metamorphosis at 11-12 mm SL. At around 18 mm SL, squamation ends, first barbels develop and the sagittae otolith primordium is closed. The length-at-metamorphosis for M. furnieri was established between 9 to 18 mm SL, since all developmental characters studied highly overlapped at that interval. All those processes are indicative of the beginning of the juvenile period associated to the settlement and the start of a bottom-oriented life-style.

scholarly journals ON THE EARLY STAGES OF FOUR GEOMETRID MOTHS

1880 ◽  
Vol 12 (11) ◽  
pp. 235-236 ◽  
Author(s):  
L. W. Goodell
Keyword(s):  
Anterior Part ◽  
Black Spot ◽  
Mature Larva ◽  
Early Stages ◽  
Yellowish Green ◽  
Brown Body

Ochyria designata, Pack.Mature larva, five specimens.—Head roundish, flattened, as wide as the first segment, yellowish green ; jaws brown. Body thickest at the 9th segment, attenuated anteriorly; yellowish green, the dorsal and subdorsal spaces reticulated and lined with brown ; a narrow stigmatal brown line and a dorsal row of triangular brown spots, one each on the 4th, 9th and 10th segments, and two on each of the intermediate ones; a minute substigmatal black spot on the anterior part of each segment from the 6th to 9th.

NOTES ON THE EARLY STAGES OF SOME MOTHS

1877 ◽  
Vol 9 (4) ◽  
pp. 61-63
Author(s):  
L. W. Goodell
Keyword(s):  
The Body ◽  
Early Stages ◽  
11Th Segment ◽  
Yellowish White

Larva, I example–Body smooth, thick and uniform to the 11th segment, from which it tapers abruptly to the end. Cinnamon brown; a large sub-dorsal, velvety, dark brown shade on the 4th, 5th and 11th rings, and on each of the remaining rings, except the three first and last one, is a dorsal curved line, and two small roundish spots of the same color; two larger, square, dark brown dorsal spots edged with yellowish-white, on the first ring.Head roundish, as wide as the body.

scholarly journals The development of the Weberian ossicles and anterior vertebrae in the goldfish

1939 ◽  
Vol 127 (849) ◽  
pp. 452-472 ◽  
Keyword(s):  
Carassius Auratus ◽  
Vertebral Column ◽  
Anterior Part ◽  
Interesting Problem ◽  
Early Stages ◽  
Difference Of Opinion

The study of the development of the anterior part of the vertebral column in the goldfish, Carassius auratus (L), presents an interesting problem on account of the modification associated with the presence of the Weberian ossicles. Although much descriptive and anatomical work has been done on the Weberian ossicles, the early stages of their development have been described only by Nusbaum (1881) in the carp and by Matveiev (1929) in the rudd, who are by no means wholly in agreement with regard to the method of origin. Some difference of opinion also exists with regard to the existence of separate intercalary elements in the anterior part of the vertebral column of teleosts. In this investigation of the development of the anterior vertebrae and Weberian ossicles of the goldfish it has been my endeavour to elucidate these points.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Fine structure of the rectal papillae of the oriental fruuit fly, Dacus dorsalis Hendel (Tephritidae, Diptera Insecta)

1990 ◽  
Vol 48 (3) ◽  
pp. 498-499
Author(s):  
Len Wen-Yung ◽  
Mei-Jung Lin
Keyword(s):  
Fine Structure ◽  
Cell Membrane ◽  
Intercellular Space ◽  
Anterior Part ◽  
Apical Cell ◽  
Posterior Part ◽  
Apical Cell Membrane ◽  
Dacus Dorsalis ◽  
Radial Cell ◽  
Circular Base

Four cone-shaped rectal papillae locate at the anterior part of the rectum in Dacus dorsalis fly. The circular base of the papilla protrudes into the haemolymph (Fig. 1,2) and the rest cone-shaped tip (Fig. 2) inserts in the rectal lumen. The base is surrounded with the cuticle (Fig. 5). The internal structure of the rectal papilla (Fig. 3) comprises of the cortex with the columnar epithelial cells and a rod-shaped medulla. Between them, there is the infundibular space and many trabeculae connect each other. Several tracheae insert into the papilla through the top of the medulla, then run into the cortical epithelium and locate in the intercellular space. The intercellular sinuses distribute in the posterior part of the rectal papilla.The cortex of the base divides into about thirty segments. Between segments there is a radial cell (Fig. 4). Under the cuticle, the apical cell membrane of the cortical epithelium is folded into a regular border of leaflets (Fig. 5).

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

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