The first instar nymphs of two peltoperlid stoneflies, i.e., Microperla brevicauda Kawai, 1958 of Microperlinae and Yoraperla uenoi (Kohno, 1946) of Peltoperlinae, were examined and described. Additionally, the phylogeny and groundplan of the first instar nymphs of Peltoperlidae and Plecoptera were considered. The first instar nymphs of M. brevicauda have a slender body with a prognathous head of typical shape; they represent a groundplan in Plecoptera. On the other hand, the first instar nymphs of Y. uenoi have a broad, cockroach-like body with an orthognathous and shortened head, the latter being regarded as a potential autapomorphy of Peltoperlinae. Such differences in body shape between the subfamilies are speculated to arise from heterochrony. The three-segmented cerci of Y. uenoi are characteristic to Systellognatha, whereas the four-segmented cerci of M. brevicauda were independently acquired within Microperlinae. The structure and distribution pattern of chloride cells in the first instar nymphs of Plecoptera were also discussed. The presence of coniform chloride cells is a potential groundplan of Arctoperlaria. One to two pairs of chloride cells are distributed on the first nine abdominal segments of M. brevicauda; this represents a groundplan character of Systellognatha. On the other hand, one to four pairs of chloride cells are found on the second to ninth abdominal segments of Y. uenoi; this distribution pattern may be an apomorphic groundplan of Peltoperlinae.

中文翻译：

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两个Peltoperlid stone（Insecta，Plecoptera，Peltoperlidae）的第一龄若虫

考察并描述了两种peltoperlid石蝇的初龄若虫，即Microperlinae的短小Microperla brevicauda Kawai（1958）和Peltoperlinae的Yoraperla uenoi（Kohno，1946）。此外，还考虑了小花oper科和鞘翅目的第一龄若虫的系统发育和平面图。短尾蝠的第一龄若虫具有细长的身体，具有典型形状的头顶畸形。它们代表了鞘翅目的平面图。另一方面，上野耶氏酵母的第一龄若虫具有宽大的蟑螂状体，具有正颌和短头，后者被认为是潜在的Peperoperlinae。推测亚科之间的这种体形差异是由于异时性引起的。上野耶尔森氏菌的三段式蜡ci是Systellognatha的特征，而短小支原体的四节cerci是在微细百菌科中独立获得的。还讨论了鞘翅目第一龄若虫中氯化物细胞的结构和分布模式。锥状氯化物细胞的存在是弧菌的潜在基础。一到两对氯化物细胞被分布在短小分枝杆菌的前九个腹部节段上。这代表了Systellognatha的平面图特征。另一方面，在上野耶尔森氏菌的第二至第九个腹部节段中发现了一对至四对氯化物细胞。这种分布模式可能是Peltoperlinae的无定形平面图。锥状氯化物细胞的存在是弧菌的潜在基础。一到两对氯化物细胞被分布在短小分枝杆菌的前九个腹部节段上。这代表了Systellognatha的平面图特征。另一方面，在上野耶尔森氏菌的第二至第九个腹部节段中发现了一对至四对氯化物细胞。这种分布模式可能是Peltoperlinae的无定形平面图。锥状氯化物细胞的存在是弧菌的潜在基础。一到两对氯化物细胞被分布在短小分枝杆菌的前九个腹部节段上。这代表了Systellognatha的平面图特征。另一方面，在上野耶尔森氏菌的第二至第九个腹部节段中发现了一对至四对氯化物细胞。这种分布模式可能是Peltoperlinae的无定形平面图。