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Show 1891.] ASSOCIATION OF GAMASIDS WITH ANTS. 639 considered joint work ; the observations and experiments were solely m y own, and I alone am responsible for any opinions expressed in this memoir. For the identification of the species of Ants I am indebted to the kindness of Mr. Edward Saunders. The Gamasiclce are a family of the Acarina ; Megninx considers them to be the most highly organized in the order and the nearest to the Insecta ; in spite of the absence of eyes, which are found in some other families, the great development of the brain and nervous system, and the specialization of the trophi and the alimentary and muscular organs, probably entitle them to this position. The family may be divided into four well-marked subfamilies, viz. the Pteroptince, the Dermanyssina?, the Uropodince, and the Gamasince-the last-named being far the largest. The Pteroptince are all parasites of Bats, the Dermanyssince of Birds or Bats ; these two subfamilies may be wholly omitted from consideration for the purposes of this paper ; it is amongst the Uropodince and Gamasince alone that the facts here recorded arise. Both these families are composed of creatures which in their immature stages are soft and white, but in their mature condition are fully chitinized. In the former group the chitin is very dense and hard, in the latter much thinner and tougher ; the former are mostly rather slow and inactive, the latter usually extremely quick and active. It used to be considered that the Gamasince lived wholly on vegetable matter in a decaying condition ; in the year 1880, however, when I was trying to rear a few of the species in confinement for the purpose of tracing their life-histories, I entirely failed in getting them to live upon vegetable matter, and thinking from the structure of their mouth-organs that they must be predatory, I tried them with a diet of living cheese-mites, upon which they throve admirably2. I have since usually fed them in this manner, or at all events with small Acari or Insects. Col. Blathwayt also, who has made numerous experiments upon rearing them, has adopted m y mode of feeding, apparently with complete success, he also having failed with a vegetable diet3. It is evident therefore that some species of Gamasince, probably not all, are predatory. As to the food of the Uropodince, I do not think that we have any reliable information as yet: their extremely long and slender mandibles with minute chelse seem as though intended for introduction into very narrow passages; their slowness hardly seems fitted for a predatory life, as they certainly do not construct any snare, and I have entirely failed to rear them, and so I believe has Col. Blathwayt4. 1 " Memoire sur 1'organisation et la distribution zoologique des Acariens de la famille des Garnasides." ' Robin's Journ. de l'anat. et de la pbysiol.,' May 1876, pp. 298-9. 2 " Observations on tbe Life-histories of Gamasinoe," Journ. Linn. Soc, Zool. vol. xv. (1881) p. 298. 3 " On some common Species of Gamasidse," Journ. of Mierose. and Nat. Sci. n. ser. vol. ii. 1889, p. 102. 4 It is easy to rear the creatures in large jars containing quantities of material, but then they are useless for observation. PROC. ZOOL. Soc-1891, No. XLIIL 43 |
