ANATOMY OF THE LARVA OF ALETIA. 47 



the two lips, and so close the opening between them ; the other i)art is 

 attached to the neighboring epidermis, and serves to open the lips. 

 Only this latter division of the muscle, which is considerably the larger, 

 was described by Landois.* 



The internal anatomy of the larva agrees closely with the lepidopte- 

 roiis type, as established by previous observers. In the head, Plate YII, 

 Fig. 1, the digestive canal begins with the large mouth m, lined by a 

 dark, firm cuticuhi and passing over into the narrow muscular oesopha- 

 gus, Oe, Behind the mouth is a projecting pointed process at the tip 

 of which opens the salivary duct. Above and in front of the mouth 

 there is a distinct mass of tissue, of a fibrous, areolar character, spread- 

 ing out fan-like from the upper wall of the oesophagus and attached 

 in front to the lower part of the clypeus and to an endocranial pro- 

 cess. In this mass of tissue lies the small frontal ganglion. Above the 

 oesophagus is the brain, ir; below it the subcesophageal ganglion S, 

 connected by a short commissure with the first ganglion of the ventral 

 chain. 



The rest of the internal anatomy is illustrated by Fig. 1, Plate YI. In 

 the first (thoracic) segment the oesoj^hagus expands into the enormous 

 stomach St.^ which runs through eight segments, and is by far the larg- 

 est and most conspicuous organ of the body. From in front backwards 

 it gradually widens, but posteriorly it is rounded off. Into the hinder 

 end open the malpighian or urinary vessels m. v., six in number, three 

 on each side uniting together and opening by a short duct. The sali- 

 vary glands lie upou each side of the stomach, having long ducts 

 which reach through the anterior three segments of the body. The 

 gland proper, Sal., is an elongated tube, gradually diminishing in diam- 

 eter towards its posterior end or tip; its course is curious; it runs some 

 distance straight backwards, then makes a sharp angle over the second 

 proleg and runs forwards and upwards, then another sharp crook over 

 the first proleg and it continues backwards again and slightly upwards. 

 Behind the stomach the intestinal canal consists of four parts: first a 

 short, constricted connecting: i)iece; second a dilated, oval division. In.; 

 third the short rectum E. ; fourth the short anal tube. The dorsal ves- 

 sel or heart, d, v., is a long tube placed above the digestive canal, and 

 extending through nearly the entire length of the body. The ventral 

 chain of ganglia numbers eleven distinct knots, the last being however 

 evidently double. The first ventral ganglion is the subcesoi^liageal; 

 the second lies so near it as to be almost united with it. The others lie 

 at regular intervals, until the tenth, which is pushed a little forward of 

 its original position over the fourth proleg. The eleventh double gan- 

 glion lies close to the tenth and gives off a large number of nerves, 

 most of which run backwards. 



The large stomach alone represents the entodermic canal, and presents 



*Laiidoia. Zeit. "wiss. Zoologie, 1867. 



