Development of Lonclioptera. 343 



the other on the first segment of the body, immediately behind 

 the head. From the one spiracle to the other, the trachea runs 

 in a gently undulating course, and without any material alteration 

 of size. The two lateral tracheae are connected together by two 

 transverse branches (PI. XI. fig. 1,^), one of which is situated in 

 the first segment of the body, the other in the last. In addition the 

 lateral tracheae give off two small branches in the posterior seg- 

 ment and one in each of the others.* 



Digestive Organs. — The digestive organs may be divided into 

 pharynx, oesophagus, crop, stomach, intestine and rectum, with 

 the malpighian vessels and salivary glands as accessary organs. 



The pharynx is strengthened in front by a scaffolding of chitine. 

 It has a length of about 43-*'^ ^^ ^" inch, and is shuttle-shaped, 

 tapering slightly at each end. It is strengthened by being thrown 

 into longitudinal folds, which run from one end to the other at 

 distances of about :jg^th of an inch, and between which again the 

 membrance appears to form both longitudinal and transverse folds. 

 The latter, however, are very close together, and are, perhaps, 

 small chitinous thickenings of the membrane. 



The oesophagus is narrow and cylindrical. It is 2V'-'' ^^ ^" 

 inch in length and only g^o*-^ '" diameter. 



The crop is small and sphaerical ; in my first specimen it was 

 divided into two parts by a central constriction. The second speci- 

 men however, which had been preserved in spirits of wine, did not 

 show any such structure. In living animals, or in those just dead, 

 the form of the stomach depends, no doubt, very much on the 

 condition of the strong transverse muscles with which it is pro- 

 vided. In my specimen, which had been in spirits, it was simply 

 fusiform. 



The malpighian vessels are long, and, I think, four in number, 

 but upon this point I am unable to speak positively. 



The salivary glands are large. In form they are cylindrical, 

 and are connected with the mouth by short branched tubes. The 

 glands are formed of large cells, the walls of which can in most 

 cases easily be perceived. They are about -jl^^th of an inch in 

 diameter, with a nucleus about -g^oth of an inch, and a small 

 nucleolus. 



Nervous System. — The sub-oesophageal portion of the nervous 

 system is condensed into a single mass, as is usually the case 

 where the segments do not admit of much motion. In the pre- 



* I do not find, however, in my sketch from which fig. 1 , PI. XI. is taken, any 

 branch in the two first segments. 



