小麦茎蜂在太白县咀头镇地区常年点片发生。其幼虫主要蛀食麦茎的髓及韧皮部,影响籽粒灌浆,造成小麦减产。79年以来,对其发生规律进行了如下初步观察。形态特征成虫:体黑色。翅深茶褐色,阳光下有紫色闪光。头黑色,复眼大,具三个单眼,触角线状,末端稍膨大。胸部黑色。腹部细长,背观粗细均匀。后足长。前、中足的腿节黑色,胫节和附节黄色。后足腿节和跗节黑色、胫节上半部黄色末端黑色。跗节均由五节组成,各足胫节末端内侧有2距。雌虫:体长8—10毫米,翅展18—20毫米,腹部第三、五、六节两侧有米黄色椭圆斑。产卵器针状、暗红色。雄虫:体长6—8毫米, Wheat stem bee in the town of Taibai Tsui town perennial dot film occurs. The larvae mainly eaten wheat stems marrow and phloem, affecting grain filling, resulting in wheat yield. 79 years since the occurrence of the rules of the following preliminary observations. Morphological characteristics Adult: black body. Dark brown wings, a purple flash in the sun. Head black, compound eyes large, with three monocular, tentacles linear, the terminal slightly swollen. Chest black. Abdomen slender, back view thickness uniform. Hind foot length. Front, midfoot leg black, tibia and appendage yellow. Hind legs section and knot black, tibia upper part of the yellow end black. Knuckles are composed of five sections, each tibia distal medial 2 distance. Female: body length 8-10 mm, wingspan 18-20 mm, abdomen third, five or six on both sides with beige oval spots. Ovipose needle, dark red. Male insects: body length 6-8 mm,