【Aim】 Eysarcoris aeneus, a main pest of many economic crops, is widely distributed in Palaearctic region with humeri variable. Difference in the humerus length of “rounded humerus form” and “needle-like humerus form” suggests that intraspecific variation may exist in E. aeneus. 【Methods】 In this study, 142 specimens (98 for E. aeneus and 44 for the outgroup E. ventralis ) from 19 regions of China were examined to ascertain the morphological variation of four characters (forewing, hindwing, head and scutellum) between the two forms, “rounded humerus form” and “needle-like humerus form”, respectively, of E. aeneus with the use of geometric morphometrics approaches, including multivariate regression, principal component analysis (PCA), canonical variate analysis (CVA) and discriminant function analysis (DFA). 【Results】 Allometry was not found in all of the four characters (forewing, hindwing, head and scutellum) examined. For the four characters, though the principal component analysis showed overlap between the two forms of E. aeneus, the canonical variate analysis showed significant differences between them (P-values for Procrustes distance and Mahalanobis distance were all less than 0.01). The correctly assigned percentages of “rounded humerus form” and “needle-like humerus form” ranged from 67% to 89% specimens based on the four characters using the discriminant function analysis. 【Conclusion】 This study proved that forewing, hindwing, head and scutellum can serve efficient evaluation criteria in describing intraspecific morphological difference of E. aeneus, and scutellum is the most informative character. The geometric morphometric descriptors showed significant shape differences and overlapped centroid size between the two forms of E. aeneus, indicating that the analysis of shape is more sensitive for detecting differences among lineages than that of size. Our study shows that geometric morphometrics is efficient in describing intraspecific morphological difference of E. aeneus, and lays a foundation for intraspecific variation studies of stink bugs in future.

【Aim】 The aim of this study is to discover the morphological details for accurate identification and differentiation of Culicoides species. 【Methods】 The morphological details of adult Culicoides newsteadi Austen were observed under light microscopy (LM) and scanning electron microscopy (SEM). Important diagnostic features of the compound eyes, antennae, maxillary palpus, mouthparts, mesonotum, scutellum, wing, hind tibia, claws and the genitalia of both females and males were described. 【Results】 Six types of antennal sensilla were found in adult females of C. newsteadi including sensilla coeloconica, short sensilla trichodea, long sensilla trichodea, sensilla chaetica, straight sensilla basiconica, and curved sensilla basiconica scattered on antennal surface. Scutal areolae in adult females and males are ovoid. The tips of the parameres in adult males have complicated branches. Compound eyes in adult females have a short distance about 1.3 facets at the joint. The mandible in adult females has 14-17 triangular teeth. The hind tibial comb in adult females has 16-19 combs. 【Conclusion】 The morphological features obtained by LM and SEM can provide information not only for taxonomy and phylogeny of Ceratopogonidae, but also aid in epidemiology studies and disease control, as well as in the digitization, three-dimensional analysis and networking of morphological information of Ceratopogonidae.