288 Mr. Ernest Ewart Unwin on the 
each of the remaining ribs has a pair of fringes, and in 
cross-section resembles the letter Y—the two arms being 
the fringes and the stem the supporting rib. The cavity 
of the strainer is thus divided into a series of eight lower 
compartments and a single upper one.” * 
The salivary glands in the Drosophila larva are not so 
large as those of the blow-fly. The intestine, too, is less 
coiled in the former larva. 
Nervous System.—The nervous mass, which corresponds 
to the brain and ventral cord of Chironomus, is situated in 
the metathoracic segment. It consists of a well-marked 
Gere: 
Transverse section through the pharynx of a late larva. (x 100.) 
a.sp., antérior digitate spiracle ; /., single filament of same ; 
stv., pharyngeal straining apparatus. 
“brain” and a “ventral complex”; I have to thank Pro- 
fessor Miall for this convenient name. The paired nerves 
indicate its segmental character, a pair of nerves being given 
off to each segment of the body. The cesophagus pierces 
the nerve mass lying between the hemispheres and the 
ventral complex + (fig. 2). 
Heart and Circulation—There is nothing worthy of 
special note in the heart and circulatory system of 
Drosophila.t In a living larva the pulsations of the 
posterior end of the dorsal vessel, the so-called heart, can 
be seen. The exact extent of the “heart” cannot be 
* Wilkinson (1901). + Lowne (1890-95), p. 68. 
{ Lowne (1890-95), pp. 87-91. 
