'?73 Vol. 50, pp. 35-42 April 21, 1937 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGT STUDIES IN AMERICAN SPIDERS: THE AIGOLA CHAMBERLIN. BY C. R. CROSBY. There has been great uncertainty as to the genera in which many of the American species of Linyphiiae should be placed. As a first attempt in this direction we here bring together the species congeneric with Microneta crassimana Emerton. All of these species are very rare and the females are either unknown or there is considerable uncertainty as to how they should be matched with the males. AIGOLA Chamberlin. N. Y. Ent. Soc. Jour. 29 : 36, 1921. Type.— Aigola pavlina Chamberlin which equals Microneta crassimana Emerton. The species here placed in Aigola are all rather closely related to each other. They form a compact group in that great complex of species com-prised in the old genera Lepthyphantes and Microneta. It is very difficult, if not impossible, to differentiate this genus on general characters, such as form of thorax, number and position of teeth or spines, or eye arrangement, but a good character is to be found in the genital bulb. In this group of species the radix is broader than usual, roughly triangular, the apex pro-duced so far forward that it forms a notch in which the embolus lies. The embolus is not of the long, thin, folded and strongly curved type of Lepthy-phantes and Microneta (in the wide sense), but is much more simple, smaller, and built on a different plan as described under the various species. Aigola crassimana Emerton. Figs. 1-2. Microneta crassimana Emerton, Conn. Acad. Sci. Trans. 6 : 75, pi. 24, f. 3. 1882. Gongylidium tuberosum Emerton, Conn. Acad. Sci. Trans. 20 : 150, pi. 2, f. 5. 1915. 13— Proc. Biol. Soc. Wash., Vol. 50, 1937. (35) ^ ,<*-1-■r
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