304 
CLASS VIII. 
represented by this ligula. The mawille are two small plates at 
whose base are attached the feelers stretching forwards, and which 
were formerly regarded as antenne ; they have four oblong joints, 
of which the second and the fourth are the longest. 
The intestinal canal of the Flea is short and straight ; its stomach 
is cylindrical, the small intestine as long as the stomach, and rectum 
short. There are four short and wide urinary tubes, which are 
implanted at the inferior orifice of the stomach. At both sides are 
two salivary vessels in form of round vesicles, whose efferent ducts 
coalesce to form a canal on each side of the cesophagus, which 
mounts tortuously to the mouth. 
See Rampour, Abhandlung ib. d. Verdauungswerkzeuge der Insecten, 
S202. Nabi xxl. fies (2), 
Comp. on this family A. Ducks, Recherches sur les Caractéres 
soologiques du genre Pulex, et sur la multiplicité des espéces qwil 
renferme. Ann. des Sc. nat. xxvu. 1832, pp. 165—175, Pl. 1v., and 
P. F. Boucut, Bemerkungen tiber die Gattung Pulex, Nov. Act. 
Acad. Ces. Leop. Car. Tom. xvit. 1835, p. 501—508 (this writer 
considers the parts indicated above as mandibles to be lacinie of 
the under-lip, and gives the maxillary palps five joints). 
Sp. Pulex irritans L. (in part), Hooke Micrographia Tab. 34 (a large 
figure of full 15 Rhenish inches, or 4 decimeters in length), Ducés 1. 1 
fig. 1 (both figures represent the female). Ordinarily this species is con- 
founded with others which occur on the dog and domestic cat, Pulex canis 
Duaks, Pulex canis and Pulex felis Boucué. To the last-named refer the 
figures of RoxsEL, Ins. 11. Muscar. atque Culicwm, Tab. u—r1v. (Tab. 11. 
fig. Io, representing a male, refers according to BOUCHE to Pulex irritans). 
Moreover these species can bear leaving their natural habitat for a time, 
and thus Pulex irritans may pass on to dogs, Pulex canis onto man. A 
particular species also occurs on fowls, Pul. galline, SCHRANK, BoucHs, 
All the species of this genus are small insects ; the largest hitherto known, 
Pulex gigas, has only a length of two lines, Fauna Bor. Americana of 
J. Ricwarpson, Vol. iv. 1837. The hip (coxa) of the feet is as large as 
the thigh (femur) and very thick; the fore-feet are placed far forwards, 
almost under the head. The abdomen is large, on the upper surface in the 
male, concave ; in copulation the female is placed on the back of the little 
male. The eggs are white, oblong, sticky. In the summer season the 
larvee come forth after a lapse of six days, having no feet, and resembling 
small, white worms. LEEUWENHOECK brought them up on dead flies, 
RoESEL on dead gnats and dried pigeon’s blood. Blood that has followed 
} Ducks, Ann. des’ Se. nat. sec. Série. Tom. vi. 1836. Zool. p. 130. 
