8 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
tibia I more than one and one-half times as long as broad, femora I and 
II usually not spined above; body of female without constriction 
and incomplete groove behind insertion of last pair of legs. 
Type species.—Liponyssus setosus Kolenati. 
The genus Ophionyssus Mégnin (1884) should be considered as a 
synonym of Liponyssus as was pointed out by Berlese (1917). 
The genus Liponyssus as here defined still includes most of its old 
species, among them being the following: Lepronyssus fossulatus 
Kolenati; Liponyssus corethroproctus Oudemans; Macronyssus longi- 
manus Kolenati; Liponyssus uncinatus (Canestrini); L. americanus 
Banks; L. canadensis Banks; L. bursa (Berlese); L. bacott (Hirst); 
Ichoronyssus decussatus Kolenati; L.lepidopeltis (Kolenati); L. lacer- 
tinus (Berlese); and JL. natricia (Gervais). Also the following new 
species here to be described go in this genus: L. tenucscutatus, L. 
pacyicus, and L. montanus. 
Genus DERMANYSSUS Dugés. 
In the female the chelicerae are long and needlelike, being com- 
posed of two closely adhering elements, which probably represent the 
two arms of Liponyssus. Inthe male the chelicerae are not needlelike, 
but are variously formed, both arms being always present and easily 
recognized. Dorsal shield large and undivided in both sexes; legs 
rather slender, especially the front pair. Rim of anus greatly thick- 
ened behind, and the anus itself usually situated in the posterior 
half of anal plate. 
Type species. —Dermanyssus gallinae (Redi). 
In 1913 Hirst proposed Liponyssoides as a new subgenus for a rat- 
infesting species. He stated that the capitulum was differently 
shaped from that of Dermanyssus and that the male chelicera was 
provided with a flagellum bearing a small tooth. It is to be ques- 
tioned if the type of chelicera described by Hirst is really different 
fundamentally from that of the male of D. gallinae. Therefore, it 
appears best to leave Dermanyssoides as a subgenus, denying it ge- 
neric rank. 
ALLODERMANYSSUS, new genus. 
Mouth parts similar to those of Dermanyssus. Dorsal shield in 
female divided into two plates, the posterior one being minute; in 
the male, dorsal shield attenuated posteriorly. Sternal plate squar- 
ish and with six setae. Anal plate egg shape in outline and with 
anus situated centrally. Legs as in Dermanyssus. 
Type species—Dermanyssus sanguineus Hirst. 
This genus is amply distinct from Dermanyssus, showing in the 
formation of the dorsal shield, the sternal plate, and anal plate a 
correlation of three fundamental characters. 
