The Aradidae of Canada

P. Wygod- zinsky, American Museum of Natural History, New York, N. Y. Structures and termi nologies HEAD: The head of Aradidae is of the opisthognathous type, in which the mouthparts lie posterior ventral because of a deflection of the facial portion, and is highly specialized to accommodate the sucking mouthparts suited for feeding on fungi. [...] THORAX: fn Aradus the pronotum, or the dorsal part of the lst (anterior) thoracic segment, covers posteriorly the anterior portion of the mesothorax (2nd thoracic segment), and the surface of the pronotum is provided with three pairs of longitudinal carinae (ridges), which are called median, paramedian, and lateral carinae (see Figs. [...] In the males of some species of AracJus, narrowing of wings, or stenoptery, occurs (Pl. [...] In the male of Aradus the 9th segment forms the genital capsule or pygophore; it is enclosed within the cavity formed by depression of the 8th segment and is hidden from above by the wing' In the female of Aneuru,r no median longitudinal split of the 7th sternite occurs, and the three lobes (P1. [...] In Aradus the positions of abdominal segmental spiracles (openings of the internal respiratory system) are on the ventral side of the connexiva; in Aneurus they are sometimes on the lateral edges of the latter and their positions are of taxonomic importance.