Abstract: 【Aim】 Culicoides punctatus, an important vector midge, is the main transmission vector of Schmallenberg virus (SBV). The histological structure of the internal organs and systems of adult C. punctatus was observed by paraffin section and hematoxylin-eosin (HE) staining. 【Methods】 C. punctatus adults were collected by net and light trap. With legs and wings removed, C. punctatus adults were fixed in Duboscq-Brasil fixation solution at the room temperature. Then glass slides were made after step-by-step dehydration, xylene transparency, paraffin embedding, continuous section and hematoxylin-eosin staining, and observed and photographed under light microscope. 【Results】 There is no gender difference in the digestive system of C. punctatus adults, which is composed of the digestive tract and salivary glands. The central nervous system is composed of the brain and the ventral nerve cord. The brain can be divided into three functional areas, i.e. protocerebrum, deutocerebrum and tritocerebrum. The compound eyes and antennae are the main sensory organs. The ventral nerve cord is divided into subpharyngeal ganglion, thoracic ganglion and ventral ganglion. The respiratory system mainly consists of tracheas, which are distributed all over the body and have no lung tissue. The thorax has two pairs of valves, which are located in the mesothorax and metathorax. The air sac tissue is vesicular and not obviously stained. The reproductive system includes internal and external reproductive organs, the female internal reproductive organs mainly include ovary, fallopian tube, seminal vesicle and accessory glands, and the male internal reproductive organs mainly include testis, vas deferens, ejaculatory duct and accessory glands. 【Conclusion】 This study ascertained the structural characteristics of the digestive system, nervous system, respiratory system, reproductive system and sensory organs of C. punctatus adults, providing more direct and accurate evidence for the study on the development of Culicoides and being helpful to improve the comprehensiveness and accuracy of monitoring, forecast and control of biting midges.

Key words: Culicoides punctatus, organs and systems, histological structure, paraffin section, hematoxylin-eosin (HE) staining