Hygrobates in Koenike 1909

In his book Acarina, Milben in Die Süsswasserfauna Deutschlands published in 1909 Koenike gave some figures for the Hygrobates species known by him at this date.
This book is written in German and I’m not able to translate all the text. This article reproduce the informations and figures of all these Hygrobates. Sometimes, the name has changed, I give th new name in this case. I’ve already published an other article of the same kind about the Hygrobates in Piersig 1897.

Hygrobates longipalpis (Herman)

Page 85. Fig 128 Female

Size of female up to 2.5mm

Hygrobates reticulatus (Kramer)

Actual name : Hygrobates foreli (Lebert, 1874)
Page 86. Fig 129 Female
Size of female : 1.5mm
Size of male : 1.2mm

Hygrobates calliger (Piersig)

Page 86. Fig 130 Female
Size of female : 0.8mm
Size of male : 0.65mm

Hygrobates trigonicus (Koenike)

Page 87. Fig 131 Female.
Size of female : 0.65mm

Hygrobates titubans (Koenike).

Actual name : Hygrobates foreli (Lebert, 1874)
Page 87. Fig 132 Female
Size of female : 0.8mm

Hygrobates nigromaculatus (Lebert)

Page 88. Fig 133 Female
Size of female : 1.5mm.

Hygrobates nigromaculatus ramosus (Piersig)

Actual name : Hygrobates nigromaculatus Lebert, 1879
Page 88.

Hygrobates porrectus (Koenike)

Page 88. Fig 134 Female.
Size of female : 0.7mm

Hygrobates norvegicus (Sig Thor)

Page 89. Fig 135.
Size of female : 1.2mm.
Size of male : 0.9mm.
Female : 18 to 25 acatabula on each genital plate.

Key of Hygrobates by Koenike

Key given in German

Bestimmungstabelle für die Arten.
I. Mit 6 Geschlechtsnäpfen.
1 . Körper kurz.
1) Mit 1 Zapfen am 2. Palpengliede.
a. 4. Epimere innen breit abgerundet. =>1. H. longipalpis.
b. 1. Epimere innen spitz vorspringend.
aa) Haut netzartig gefeldert. =>2. H. reticulatus.
bb) Haut gerippt. =>3. H. calliger.
2) Statt des Palpenzapfens mit Wulst.
a. 4. Epimere innen spitz. =>4. H. trigonicus.
b. 1. Epimere innen breit abgerundet. .=>5. H. titubans.
3) 2. Palpenglied ohne Zapfen und Wulst. =>6. H. nigromaculatus.
2. Körper lang gestreckt. 7. H. porrectus.
II. Mit zahlreichen Geschlechtsnäpfen. =>8. H. norvegicus.

Key for the identification of the species.

Attempt of translation. (with the help of Google Translate)

I. With 6 acetabula.
1 . Body short.
1) With a pin on the 2nd segment of palpi.
a. 4. fourth Epimers broadly rounded inside . 1. H. longipalpis.
b. 1. First Epimers pointed inward protruding. .
aa) checkered with skin like a net . =>2. H. reticulatus.
bb) skin ripped . =>3. H. calliger.
2) With a bead on the palps kingpin (a bead instead of a pin on the second segment of palp ???)
a. fourth Epimers pointed inward . =>4. H. trigonicus.
b. 1. First Epimers broadly rounded inside .=>5. H. titubans.
3) 2. Palps without pin and bead . =>6. H. nigromaculatus.
2. Body elongated. => 7. H. porrectus.
II. With numerous acetabula. =>8. H. norvegicus.

Reference :

• Koenike, F (1909) Acarina, Milben in Die Süsswasserfauna Deutschlands