122 SUMMARY OF CURRENT RESEARCHES RELATING TO 
Mallophaga from Land-Birds.* — Prof. Y. L. Kellogg not only de- 
scribes some new Mallopbaga from American land-birds, but gives an 
account of the mouth-parts of these ectoparasites. 
The parts in question are found to be distinctly fitted for biting ; 
there is nothing which lends any probability to the old theory that the 
Mallophaga suck their food. The author has, indeed, seen these parasites 
biting off and eating bits of feathers, and the crop always contains tiny 
bits of feathers. 
The Mallophaga seem to certainly belong to the group Platyptera, 
and it is, therefore, with other members of that group that the author 
compares their mouth-parts. There is a peculiar and interesting simi- 
larity of mouth-structures between the Mallophaga and the Psocidee ; 
the latter, it is important to note, have somewhat similar feeding habits 
to the former, for they live on dry dead organic matter, such as wood 
and paper, dried insects, dried bird and mammal skins. 
The author concludes with a list of hosts and parasites. 
S. Araclinida. 
Hydraehnida of Germany.^ — Dr. R. Piersig has published the first 
part of a beautifully illustrated monograph on the Hydraehnida of 
Germany. He gives a history of previous researches dealing with this 
group. The family Hydrachnidae is divided into five sub-families : — 
Hygrobatinse, Hydryphantinre, Eyla'inae, Hydrachninre, and Limno- 
charinae. The Hydrachnidse live wholly in water, almost all in fresh 
water. They are marked by the compressed body, unsegmented trunk, 
5-jointed palps, and 6-jointed feet usually ending in a double claw. The 
mouth-parts form a suctorial proboscis ; the mandibles are distinctly 
2-jointed except in Hydrachninae. There are four anterior lateral eyes, 
usually fused into a double eye on each side ; and there may also be an 
unpaired median eye-spot. There are two tracheal stigmata above the 
mouth-opening, leading into air-reservoirs, and thence (except in Atax) 
into tracheae. In addition a skin respiration is probably general. There 
is no heart nor vascular system. The alimentary system has marked 
resemblances with that of Trombidia. A ganglionic mass pierced by 
the gullet represents brain and nerve-cord. The sexes are separate and 
the females oviparous. The animals live on Crustaceans, dipterous 
larvae, and Infusorians. They are very hardy; thus many can resist 
considerable salinity. Their distribution seems mainly due to insects. 
Structure of Gamasidse.J — Sig. F. Neri describes the common Der- 
manyssus gallinse Redi ; the soft, depressed, oval body ; the membranous, 
transparent, slightly chitinised integument; the variable coloration, 
partly depending on the contents of the ? gut ; the rapid movements of 
the four pairs of limbs ; the strongly developed striped muscles ; the 
rostrum, buccal cavity, pharynx, oesophagus, stomach, stomachic diverti- 
cula, and intestine ; the tracheal respiration ; the two dorsal tubes 
which seem to be excretory ; the sexual differences ; the copulation ; the 
* Proc. Calif. Acad. Sci., vi. (1896) pp. 431-548 (14 pis.) ; also separately Leland 
Stanford jr. University. 
t Bibliotheca Zool. (Leuckart and Chun), Heft 22, pp. 1-80 (8 pis.), Stuttgart, 
1897. X Atti Soc. Tosc. Sci. Nat., x. (1896) pp. 126-38. 
