16 
[May 2, 
Tlie oeso[>liagiis is seen to be Ioiil? and slender. Tlie slight 
enlargement at tlie end is, however, the incii)ient proventriculus. 
The rest of the alimentary canal at this stage has not yet been 
differentiated into stomach and intestine, but begins at the pos- 
terior end of the head and continues to the end of the body as a 
larger thick tube of the same size throughout its length. 
The completely formed digestive tract is seen in Fig. 2, 
representing an older larva drawn and presented to me by the 
late Edward Burgess. The oesophagus is now seen to pass 
near the hinder end of the 1st thoracic segment into a small 
spherical proventriculus. The true stomach extends to near the 
posterior third of the body, as far as the 9th segment behind the 
head, while the slender intestine is represented as twice bent 
upon itself, first in the ^senultimate segment, and a second time 
at a point in front under the suture between the 9th and 10th 
segments. 
In Mr. Burgess's di-awing (Fig. 2), no salivary glands are 
represented, neither are they by Bonnet, and I am inclined to 
think that they are wanting. 
Fig. 2. Larva of Pulex ccDiis ; p, proventriculus; s«, stomach;/, intes- 
tine; A, hr, brain, and six succeeding ganglia. — Burgess del. 
The urinary tubes are not represented by Burgess nor by Bonnet, 
but 1 am inclined to think that there is at least a pair of them, 
