40 MR. LUBBOCK ON THE DISTRIBUTION 



those of the salivary glands. In JEJristalis the trachere resembled those of the stomach ; 

 in Ilusca they were perhaps rather more like those of the colon. The arrangement in 

 Tiptda is quite different, not being in tufts. In A2oliro2)hora (PI. II. fig. 16) they are 

 much Like those of the recurrent intestine and the Malpighian vessels. 



In the larva of Bombus miiscorum the tracheae resemble those of the stomach. The 

 different systems cross one another a goo"d deal. The tracheae are stiff and wand-like, and 

 end in small tufts of from two to four, long, straight, or gently curved tubules. These 

 latter sometimes, though not often, branch dichotomously. In the larva of Laminjris the 

 tracheae on the duodenum were like those on the ilium. 



Colon. (PL IV. figs. 1 to 7.) 



In Boinhus terrestris, B. muscorum, and B. Icqyidarins, the colon (PI. IV. fig. 2) was 

 but poorly supplied, and the tracheee were long, with only a few branchlets. 



In Vespa the wall of the colon is divided into six parts, which have a ceUular appear- 

 ance, and are united to one another by their membranes. These membranes have no 

 tracheae, but a large branch runs along each of the divisions, and gives off numerous side 

 branchlets, a part of one of which is represented in PI. IV. fig. 5. 



In OpJiion lateum the rectum contains a good many round glands ? which, as usual, are 

 well supplied with tracheae. The mode of branching is much like that in Chrysopa 

 (PL IV. fig. 4). In TentJiredo and Atlialia spjinamm the colon contains six ellip- 

 tical sliield-like glands, which, as visual, are more richly supplied than the rest of the 

 organ. The mode of branching is much like that of Ophion and Chrysopa. In Ichneumon 

 also the rectal glands and their tracheae are as in Tenthredo. In Acheta the walls of the 

 organ are divided into six compartments, each of which has a double series of tracheae, two 

 large branches distributing themselves from near the middle, one to the front part, the 

 other behind. The figure (PL IV. fig. 6) which represents the front part of one division 

 will give a more correct idea than any description could do. The colon of Locitsta much 

 resembles that of Acheta. The type is very nearly the same in Giyllns ; but the lateral 

 branchlets are fewer and longer. On the colon of the larva of Acheta the tracheae resemble 

 those of the imago. 



In Forficula aurictilaria the colon contains six round shield-like glands in two alternate 

 rows. In Carabiis it is well supplied, and the larger branches anastomose a good deal. 

 The muscles make it somewhat difficult to follow the ramifications of the finer branches ; 

 but they seemed to be like those on the egg-tubes. In Ceramhyx the tracheae seemed to 

 resemble those on the stomach, as was also the case with the larvae of Lampyris and 

 Lucaniis. In Necropjhorus vespillo and N. hmnator they are almost as in Bombus ; but 

 the branchlets are longer. In Libellula there are six wide longitudinal bands, connected 

 by a membrane without any tracheae ; each band has a large trachea, which gives off about 

 six systems of branchlets. Panorpa has also six rectal glands, each with a system of 

 tracheee radiating from the centre. In Limnephilus vitratus there were at least twenty- 

 five round glands, on which the distribution of the tracheae was not unlike that of Chry- 

 sopa. Chrysopa has six round glands, as in Tenthredo, &c. The mode of tracheal dis- 

 tribution in the glands and svirrounding membrane is represented in PL IV. fig. 4. In 



