e. Head rounded in front ([fig. 92a]). Dog flea. C. canis
ee. Head long and flat ([fig. 92b]). Cat flea. C. felis
dd. Neither head nor pronotum with ctenidium. Labial palpi asymmetrical, membranous behind. Pulicidæ
e. Mesosternite narrow, without internal rod-like thickening from the insertion of the coxæ upwards. Human flea, etc. Pulex L.
ee. Mesosternite broad with a rod-like internal thickening from the insertion of the coxæ upwards ([fig. 89]). X. (Lœmopsylla) cheopis, plague or rat flea. Xenopsylla
cc. Thorax much shorter than the head and than the first tergite. Echidnophagidæ. E. gallinacea, the hen flea also attacks man ([fig. 96]). (= Argopsylla = Xestopsylla) Echidnophaga Olliff.
FOOTNOTES:
[E] Adapted from Banks, Nuttall, Warburton, Stiles, et al.
[F] Dr. C. W. Stiles considers the species which is responsible for spotted fever distinct from the venustus of Banks, separating it as follows:
Goblet cells about 75 in the male or 105 in the female. Texas. D. venustus.