|
The black-tailed skimmer, ''Orthetrum cancellatum'', is a dragonfly of Europe and Asia. It occurs nearly all of Europe except northern UK and Scandinavia; to the east, the range extends to Kashmir and Mongolia. The adult male has a blue abdomen with a black tip and transparent wings, and the female has a yellow (later: brown) body with black bands along the abdomen and transparent wings. Even the immature males look that way. This species has expanded its range, assisted by the creation of gravel pits which give it the extensive open unvegetated areas it prefers. It was first recorded in Great Britain in Essex in 1934. It is decreasing rapidly in the Maltese Islands. == Description == The black-tailed skimmer is a fairly large dragonfly (the length of 44–50 mm, 29–35 mm abdomen, rear wing 35–41 mm.) with relatively broad, flattened abdomen, but not as broad as to chaser species. With age, adult males develop extensive blue pruinescence on their abdomen, offset by yellow lateral patches. The middle lobe of the pronotum is large and notched in the middle. The chest is yellow or yellowish-brown. The abdomen is more or less flattened. The base of the hind wings without a dark opaque spots. The pterostigma is dark brown or black. On the front wings pterostigma 2–3 mm long. Anal appendages black. The females and immature males are a deep yellow color, with wavy black lines dorsally on their abdomen. Males and females have the costal vein (the leading edge of the wing) yellow or black.〔(【引用サイトリンク】url=http://www.dragonflypix.com/speciespages_en/orthetrum_cancellatum.html )〕 The species is similar to its much more localized congener the White-Tailed Skimmer, but readily identifiable in the field. The males develop a blue pruinescence on the abdomen darkening to the rear with S8-10 becoming black. Its eyes are very dark green. They fly swift and low, skimming the water surface.Females retain their color and markings though they become quite grayish brown with age.This species could be confused with Keeled skimmer or Scarce chaser. Black-tailed skimmer dragonfly (Orthetrum cancellatum) young male.jpg|young male Black-tailed skimmer dragonfly (Orthetrum cancellatum) adult male.jpg|adult male Orthetrum cancellatum top.jpg|Young female Orthetrum cancellatum side.jpg|Female Dragonfly-orthetrum-cancellatum.jpg|Female 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Black-tailed skimmer」の詳細全文を読む スポンサード リンク
|