. Diptera Danica: genera and species of flies hitherto found in Denmark. Diptera. Introduction. n it may also be horizontal and rather large, as f. inst. in the Tijmlidce and Xylophagidce, especially Xylophagus. The thorax is thus chiefly formed of mesothorax. the prothorax is very small and also the metathorax; of the latter may sometimes be seen a narroAv part behind the postscutellum and between the halteres; on the ventral side sometimes a narrow metathoracic part may also be distinguished. The spiracles I take to be prothoracic and mesothoracic. Abdomen consists of a number of segments of
. Diptera Danica: genera and species of flies hitherto found in Denmark. Diptera. Introduction. n it may also be horizontal and rather large, as f. inst. in the Tijmlidce and Xylophagidce, especially Xylophagus. The thorax is thus chiefly formed of mesothorax. the prothorax is very small and also the metathorax; of the latter may sometimes be seen a narroAv part behind the postscutellum and between the halteres; on the ventral side sometimes a narrow metathoracic part may also be distinguished. The spiracles I take to be prothoracic and mesothoracic. Abdomen consists of a number of segments of which the last are generally more or less transformed; in the descriptions I give the number of not transformed segments; these are as a rule not difficult to see but sometimes one or more of the last may be small or the last may be more or less hidden. Also at the base of the abdomen the first segment may be narrow, and sometimes the first and second ventral segments may be coalesced, yet generally a suture marks the line of connexion. The legs are somewhat uniform, only they may be relatively short or on the contrary relatively long, and they may be stronger or weaker. Generafiy the somewhat sluggish and not well flying Diptera have much stronger legs than those that fly well; the species with somewhat strong legs often bear bristles on them. The tarsi are five-jointed; the last ioint bears a pair of claws which are r. ., t » . ⢠^ ^.. â ' ^ v\s. 1. Lateral view of thorax ot generally simple, but sometimes may be Drijomyza anilis. serrated or otherwise specially formed. Besides the claws there are at the end of the last joint still three organs, which may be of some systematic importance; under the claws are attached two lobes, the pulviili, these are generally organs of fastening; they may be of difi'erent, sometimes complicated, forms, and of different sizes, and sometimes they may be absent. Between the pulviili is inserted a median organ, the empodium ; this may a
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Keywords: ., bookauthorlu, bookcentury1900, bookdecade1900, booksubjectdiptera