28 AN ACCOUNT OF BRITISH FLIES. 
corrugated ; from this end arises the sma// intestine, which has a 
double flexure. The /arge intestine is swollen, and its walls are very 
much folded ; it passes into a narrow vectum. 
At the base of the chylific ventricle open four Malpighian tubules, 
each being long and coiled. 
The Respiratory System consists of two rows of lateral trachea, 
united to one another by a tracheal tube in each segment. Nine of 
these connecting tubules send off a tube to the stigmata, and other 
tubes ramify in other parts of the body. 
Nervous System.—We were unable to make out the nervous system 
of the larvee examined, so append Kunckel’s description verbatim : 
Fic. 5.—Alimentary Canal of Larva.—a, salivary gland ; 4, cesophagus; ¢, chy- 
lific ventricle ; ¢, small intestine; e, large intestine ; 7, rectum; g, Malphigian 
tubules. 
“Le systeme nerveux, composé de ganglion arrondis, reliés par de 
connectifs, et au nombre d’une paire environ par segment, n’a pas 
été assez soigneusement étudié pour que je puisse le décrire. Il en 
est de méme du systéme circulatoire.” 
The natural position of the fleas has caused much discussion. 
Lamarck considered them Diptera on account of their transformation. 
Dugés considered them nearly related to the Hymenoptera; others 
to the Hemiptera, on account of the rostral shield. 
Latreille placed the flea between the Hemiptera and Diptera, as 
did also Westwood, raising them to an order called Aphaniptera (of 
Kirby). They are now considered true Diptera, and according to 
Osten-Sacken are a degraded genus of the family to which belong 
the small Mycetophile, that live in mushrooms during their larval 
state. Their metamorphoses certainly agree in many points. The 
