This experiment is from the official website of Parasitology, School of Medicine, Shandong University.
Operation method
Gnat morphology observation experiment
Principle
The life history of the gnat is holomorphic, divided into eggs, larvae, pupae and adult four stages. Eggs, larvae, pupae in the water development, adult terrestrial, short body, dark brown or black, commonly known as "black fly" abroad. Bite harassment can cause local inflammation or even ulceration, affecting people's work and rest. Some species can transmit human and animal onchocerciasis. Move Morphological demonstration of the life history stages of the gnat: For more product details, please visit Aladdin Scientific website.
1. Eggs: triangular in shape, 0.1-0.4 mm long, with smooth and transparent shells, initially yellow and gradually turning blackish brown.
2. larvae: cylindrical, with an inflated posterior end. Mature larvae are 5-13 mm long and pupate in cocoons. The cocoon sticks to the object on which the larva lives.
3. Pupa: semi-naked cocoon type, the cocoon is made of filaments secreted by the larval silk (salivary) glands and is open at the anterior end. The head and the front of the thorax of the pupa are naked and the back end is firmly adhered to a stone or plant.
4. adult:
Head: With a pair of large and conspicuous compound eyes, the two compound eyes of the male gnat are very close to each other, while the female gnat is distinctly distant. Antennal pair, 9-12 segments. Tentacles 1 pair, in 5 segments. Stinging mouthparts.
Thorax: Anterior and posterior thorax small, mesothorax especially developed, dorsum elevated like a humpback. Wings broad, with hyaline wing membrane and well-developed longitudinal veins. Posterior thorax with a pair of balancing rods. Three pairs of feet.
Abdomen: composed of nine segments. The external genitalia of both sexes are important in species identification. 