ACARIDEA. 
Araclin. 29 
comprises the genus Ln,tr. (Isp.); the latter comprises 
Duges (8 spp.) ; Diplodontiis^ Duges (1 sp.) ; Ilydrodroma, C. L. Koch 
(2 spp., 1 new) ; Axona, Kram. (1 sp.); Forelia^ g. n. (2 spp., 1 new); 
Limnesia, C.L, Koch (4 spp.); Bygrohates^ C. L. Koch (3 spp., 1 new) ; 
Pacliygaster, Lebert (1 sp.) ; Nescea, 0. L. Koch (5 spp.) ; Atax, Fabr. 
(3 spp.). 
F. Konike, Revision von H. Lebert’s Hydrachnider des Genfer-sees. 
Z. wiss. Zool. XXXV. pp. 613-628, pi. xxx. fig. 7. 
In part A, the author discusses the literature on the subject ; in Part B, 
19 known species are noted and described; some, with their structure 
and habits, at considerable length. 
Jlydrachna elliptica, Mull., and H. orhiculata, Mull., are discussed 
comparatively ; id. 1. c. pp. 600- 603. 
Midea, Bruz., recharacterized ; id. 1. c. p. 603, pi. xxx. figs. 1-6. 
ilf. elliptica, Miill., described, p. 604, and the species discussed at great 
length, pp. 606-612. 
Hydrodroma helvetica, sp. n., Haller, 1. c. p. 49, Switzerland. 
Forelia ahumherti, sp. n., id. 1. c. p. 60. Switzerland. 
Hygrohates gracilis, sp. n., id. 1. c. p. 68, Switzerland. 
Arrhenurus perforatus, sp. n., C. F. George, Sci. Goss. 1881, p. 269, 
fig. 149, Britain. 
Axona versicolor, Miill. The male described and figured; Kramer, 
Z. ges. Naturw. liv. pp. 438 & 439, pi. iv. figs. 4-6. 
Atax histrionicus,HQYWi.: note by H. Lucas, Bull. Soc, Ent. Fr. (5) 
X. p. liv. A. crassipes;, Miill. : F. Konike notes glands found in this 
species, similar to those found among the Bydrachnidce, but excessively 
developed ; Zool. Anz. iv. pp. 356 & 357. 
Neumann, C. J. Sur le d^veloppement des Hydrachnides. Ent. Tidskr. 
i. p. 169. 
[Not seen by Recorder.] 
Gamasidai:. 
Antonio Berlese, Bull. Ent. Ital. xiii. pp. 290-292, remarks upon the 
Polymorphism and Parthenogenesis of some species of Gamasus. The 
observations refer more especially to'G. tardus, Koch, which can be 
developed from two different series of forms. There are also remarks 
(p. 292), on a case of paedogenesis. 
Kramer, P. Ueber die Principien der classification bei den Gamasiden. 
Z. ges. Naturw. liv. pp. 638-642. 
Refers to Michael’s work (infi'd), and divides the Gamasidce into two 
groups: i. Pterop/ma, larva 8-footed {Pteroptus) ii. Uropodina, 
Gamasina, larva 6-footed, Uropoda, Tracliynotus, Dermanyssus, Sejus, 
Gamasus {Nicoletia). 
Michael, A. T>. Observations on the life-histories of Gamasince, with a 
view to assist in more exact classification. J. L. S. xv. pp. 297-309, 
1881, pis. xxii. & xxiii. 
Gives the results of observations made upon individuals bred in confine- 
