Prof. Westwood also exhibited the two sexes of Narycius (Cyphonocephalus) smaragdulus, sent to him by Mr. James Wood-Mason, having been taken in the Nielgherries. One of the males exhibited was of a purple colour. The insect had remained almost unique since first described by Prof. Westwood, in 1842, in his 'Arcana Entomologica' (vol. i., p. 115).
Mr. J. Wood-Mason exhibited the two sexes of Phyllothelys Westwoodi, one of the remarkable species of Mantidæ, as to which he had observed and pointed out (in Proc. As. Soc. Beng., August, 1876, and in Ann. and Mag. Nat. Hist., 1876) that the females are distinguished by the presence either of a well -developed foliaceous frontal horn (as in Phyllocrania) or of a great vertical cephalic cone (as in Blepharis or Gongylus) from the males, wherein these processes are represented by mere rudiments; and stated that a pair of Hestias Brunneriana, another of the species in which this interesting and novel kind of distinction between the sexes had been observed, was in the collection of the British Museum, under the MS. name of Oxypilus pictipes. The latter appeared to be a species common in collections; but of the former he had hitherto seen but five specimens—three females (one a nymph) and two males—all, even the nymph, exhibiting the sexual differences referred to equally and perfectly. The specimens exhibited were, the male from Upper Tenasserim, and the female from Sibsagar, in Assam.
Mr. Mason next exhibited a beautifully executed drawing of the great stridulating spider from Assam, Mygale stridulans, in a stridulating attitude. This sketch was by Mr. S.E. Peal, who had likewise furnished Mr. Mason with a detailed description of the habits of the creature.
Mr. Mason further announced the discovery of stridulating organs in scorpions. While recently working at the anatomy of a species allied to S. afer, he had met with structures which, from his familiarity with the analogous ones in other Arthropods, crustaceans as well as insects, he had at once without hesitation determined to be sound-producing apparatus—even before he had found that sounds could be produced by them artificially by rubbing the parts together or accidentally in the mere handling of alcoholic specimens. He had, however, been enabled to place the matter beyond all doubt; for while at Bombay, waiting for the steamer, he had obtained, by a happy chance from some Hindustani conjurors, two large living scorpions belonging to another species of the same type; these, when fixed face to face on a light metal table and goaded into fury, at once commenced to beat the air with their palps and simultaneously to emit sounds, which were most distinctly audible, not only to himself, but also to the bystanders, above the clatter made by the animals in their efforts to get free, and which resembled the noise produced by continuously scraping a piece of silk fabric, or, better still, a stiff tooth-brush with ones finger-nails. The species—a gigantic
