| Phoridae is one of the largest families in Diptera. At present, more than 250 genera, 3,500 species in the family are known all over the world. It is not only very abundant, but also widely distributed. Its larvae are diversified in feeding habits, many of them are economic important. The classification system of the family is still very controversial, mainly due to difficulties of feature selection and the judgment of their polarity. Analysis of internal structures of Phoridae can provide reliable support for phylogenetic reconstruction. It also contributes to understanding the relationship between structure and function and the pest control and the effective use of beneficial insects.In this paper, the internal structures of Phoridae were focused, taking Megaselia scalaris, M. spiracularis, Dohrniphora cornuta and Diplonevra peregrina as example. A series of experimental methods for specimen anatomizing, fixing, sectioning, and staining were developed. Using this technique, digestive, excretory, nervous, respiratory, circulatory and reproductive systems were studied detailed for the first time. Results are as follows:1.The alimentary canal of the flies were anatomized, its characteristics were displayed and analyzed. It consists of a long canal dividing as foregut, midgut and hindgut. The crop is bifoliate which located at rear of the digestive tract. It connected with oesophagous with a very fine tube. The midgut is very long and without stomach caeca structure. According to morphological features, it can be distinguished to the two regions, namely Secretion area and the absorption area. The rectal pad of hindgut is consists of four papillae. One pair of salivary glands is free in body cavity,which are opening to the maxillae and ending at the first abdominal segment.2.The insertion and the number of Malpighian tube were identified. Four Malpighian tube were divided in two groups according to their morphology and the moving trends. Their functions may different.3.The central nervous system were successfully anatomized and observed, and its function sections were displayed and analysed. The brain of phorid flies is with a typical nervous system, which all sections-protocerebrum, deutocerebrum and tritocerebrum, are distinguished clearly. Three individual ganglions from mouthparts integrates into suboesophageal ganglion. Nerve fibers are mainly distributed in abdomen.4.The distribution of tracheal system and the spiracle structure of Phoridae were dissected and observed with the help of section technique. The spiracle structures are with hairs in inner sides and different at thorax and abdomen. The spiracle structure is with retractable structure.5.Dorsal vessel and accessory pulsatile organs of phorid flies were found for first time. The dorsal vessel was not so developed that the ventricles were not identified. The accessory pulsatile organs were found in the base of antennae.6.The female reproductive system was clearly identified. It includes a pair of ovaries, a pair of lateral oviducts, a common oviduct, a spermatheca gland and a pairs of accessory glands. A ventral sclerotized ring was located on the surface of spermatheca. Based on the judgment of three phorid species, the direction of evolution of the three genera was speculated.7.The male reproductive system was clearly identified. It include a pair of testes, a pair of seminiferous ducts, a ejaculatory duct, a pair of male reproductive glands。 Seminal vesicle structure was not yet found. It is assumed that accessory glands play a role of vesicles. |
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