Dr. Leach’s Arrangement of the Crustacea^ <^c. 397 
Stirps 1. 
Kostrum et palpi exserti. 
Gen. 6. Argas, Latr. 
Gen. 7. Ixodes, Latr. 
The following species (five of which are new) were described 
from living specimens. 
Spec. 1. Ixodes plurnbeus. 
Ix. scnto cordiformi, rostro cum vagin^ pedibusque pallidb ferru- 
gineis, abdomine plumbeo. 
Long. Corp. i unc. 
Habitat in corpore et nido Hirundinis ripariffi. 
Rostrum et vagina breves, pallidh ferrugineae. Scutum parvum 
subrugulosum ferruginatum, cordiforme, inargine antico angustb 
pallido. Coxae pedumque articuli pallidi. 
Spec. 2. Ixodes hexagonus. 
Ix. scuto obscurh hexagono cum vagind pedibusque ferrugineis ; 
abdomine testaceo-albido aut subplumbeo-pallido. 
Long. Corp. 5 lin. 
Habitat in Erinaceo europaeo, gluteis tenaciter adhosrens. 
Rostrum pallidum. Vagina ferruginea, apice pallida. Cly- 
peus fusco-ferrugineus utrinque triangulatim excavatus. Scutum 
saturate ferrugineum, punctatum, lineolis duabus utrinque im- 
pressis quae ultra medium paululum prodeunt. Pedes ferruginei, 
articulis apicibusque pallidis; coxae pallidiores. 
Spec. 3. Ixodes ricinus, 
Ix. scuto rotundo minore cum vagin^ pedibusque fuscis, abdo- 
mine majore colore variante. 
Acarus ricinus. Linn.., Fabr. 
Ixodes riciuus. Latr, 
3 p 2 
Long. 
