| Thoracic segments much foreshortened, coxæ and femora of hind legs very slightly enlarged | Sarcopsyllidæ. |
| Thoracic segments normal, coxæ and femora of all the legs much enlarged | Pulicidæ. |
Family. Sarcopsyllidæ (Jiggers).
| The members of this family are not confined to one host. | |
| Three genera are known and tabulate as follows:— | |
| α. Hind coxa without a patch of spines on the inside. | |
| α1. Hind femur simple | 1. Dermatophilus. |
| α2. Hind femur with a large tooth-like projection near the base | 2. Hectopsylla. |
| β. Hind coxa with a patch of short spines on the inside | 3. Echidnophaga. |
Genus. Dermatophilus, Guérin.
Dermatophilus cæcata, Enderl.
The eyes of the female vestigial. Taken on and behind the ears of Mus rattus in Brazil.
Dermatophilus penetrans, L., 1758 (Jigger, Chigoe).
Syn.: Sarcopsylla penetrans.
About 1 to 1·2 mm. in length; brown in colour. Eyes distinct. The males only occasionally visit man to bite; the fertilized female, on the other hand, bores into the skin with her head, particularly about the toes of the host, and then attains considerable dimensions. The eggs develop on the soil with a metamorphosis similar to that of the common flea.