中文摘要：

【目的】为明确麦长管蚜Sitobion avenae（Fabricius）虫龄鉴别特征，达到快速鉴别的目的。【方法】在成像观察的基础上，测定无翅型和有翅型个体不同虫龄的体长、体宽、头壳宽、触角长、腹管长和后足胫节长6项指标。【结果】麦长管蚜不同翅型个体的体长、体宽、头壳宽、触角长、腹管长和后足胫节长在虫龄问均存在显著差异，其中体长、体宽、头壳宽和触角长在相邻虫龄之间重叠程度大，后足胫节长的重叠百分比极小或无重叠；除有翅型个体4龄若蚜和成蚜之间存在13．93％的重叠外，腹管长在不同翅型的其他相邻虫龄之间重叠百分比均极小或无重叠，说明后足胫节长和腹管长可作为虫龄鉴定的主要特征。翅、触角和尾片的其他外部形态特征在虫龄间也存在一定差异：3～4龄有翅型若蚜和成蚜虫个体前胸的膨大程度及其翅的长度明显大于同一龄期的无翅型个体，可用于蚜虫翅型的分辨以及5～4龄有翅若蚜和成蚜的鉴别；麦长管蚜1和2龄若蚜触角均为5节，5～4龄若蚜和成蚜的触角均为6节；同时，除了成蚜具有完整的尾片外，1～4龄若蚜尾片均不发达，说明触角的节数和尾片的发达程度可作为麦长管蚜不同龄期形态鉴别的辅助特征。【结论】以腹管和后足胫节作为麦长管蚜虫龄鉴别的主要特征，配合其他辅助特征，如翅的大小、触角的节数以及尾片的发达程度等，可达到快速鉴别不同翅型不同龄期蚜虫的目的。

英文摘要：

[ Aim ] To determine the instars of Sitobion avenae （Fabricius） rapidly based on morphological characteristics. [ Methods ] The body length, body width, head width, antenna length, cornicle length, and hind tibia length were measured in the winged and wingless morphs of S. avenae, based on the comparisons of external morphological characteristics. [ Results ] The results indicated that the body length, body width, head width, antenna length, cornicle length, and hind tibia length are significantly different among different instars of wingless and winged morphs. The body length, body width, head width, and antenna length were observed to have high overlaps between adjacent instars. However, the hind tibia length showed low or no overlap between adjacent instars of winged and wingless morphs. Except for an overlap of 13.93% between the 4th instar nymphs and adults of the winged morph, the cornicle length displayed low or no overlap between adjacent instars of two wing morphs, indicating that the hind tibia length and cornicle length could be regarded as remarkable criteria to identify instars of two wing morphs. Other external morphological differences were also found in the antennae, wing pads, and cauda among instars. Wing pads and wing length of the 3rd -4th instar nymphs and adults are larger in the winged morph than in the wingless morph, indicating that the external morphologies of wings are useful for the determination of 3rd -4th instar nymphs and adults or wing morphs. There are five antennalsegments in 1st and 2nd instar nymphs and six antennal segments in 3rd -4th instar nymphs and adults, respectively. The cauda is well-developed in adults while incomplete in nymphs. The number of antennal segments and development degree of eauda could be used as the convenient features to divide the instars. [ Conclusion] Practice has shown that the instar stages of wing morphs could be quickly identified using the cornicle length and hind tibia length as the remarkable criteria, based on the convenient features su