38 MR. LUBBOCK ON THE DISTRIBUTION 



the Malpighian vessels fall ; and on this the tracheae resemble those of the anterior 

 division of the stomach. I have already given my reasons for considering all these 

 oro-ans as being together homologous with the stomach of other insects, though the 

 great differences in structure certainly indicate differences of function. 



On the front part of the stomach two or three fine tubules rise from the large tracheae 

 near the base of each system, and run with only one or two branches all along the main 

 branch of the system. What makes these tubules particularly conspicuous is, that while 

 they are nearly as delicate as the ordinary tubules, they are much longer, and as straight 

 as the larger branches which they accompany. 



On the round sac to which the Malpighian vessels are attached the trachege are much 

 like those of the front part of the stomach. 



The recurrent intestine of Apliropliora spmnaria is not very richly supplied. The 

 tracheEe (PL II. fig. 16) branch more or less dichotomously, and arc waved at the ends. 



MalpujUan Vessels. (PI. II. fig. 15 ; PL IV. fig. 11.) 



In Bombiis terrestris the tracheae run along the Malpighian vessels, giving off short, 

 broad branchlets at intervals. Each of these ends abruptly, and from the termination 

 spring from five to ten tubules. These tubules branch generally two or three times at 

 acute angles, and are about xiu inch long. AVhat, however, gives a very peculiar appear- 

 ance to these tracheae, is, that the tubules of each tuft, and the branches proceeding from 

 them, though somewhat divergent, are more or less parallel to one another. 



In B. mnscor-um, B. lapidarius, B. Jiortorum, Vespa vulgaris, Anthophora acervorum 

 (PL II. fig. 15), the tracheae are like those of B. terrestris. 



In OjMon luteum long tracheae run along the Malpighian vessels, and give off side- 

 liranches here and there, which form little systems. In Tentliredo they are as in Ophion, 

 but in Atludia spinarum they seem to have hardly any tracheae. 



In Acheta (larva and imago), Gryllns, Locusta, and Forjicula, a very long trachea runs 

 along each Malpighian vessel, from one end to the other, giving off minute branchlets at 

 intervals. The ends of these branchlets were ahvays filled with fluid ; and I was there- 

 fore unable to determine their mode of termination. 



In Lihellula (PL II. fig. 19) this character was carried to an extreme, and it Avas only 

 here and there that a little branchlet could be seen proceeding from the main trachea. 



In Fanorpa the Malpighian vessels were so opake that the arrangement of the tracheEe 

 could not be made out. In Chrysopa they seem to have no tracheae. In Aphrophora 

 the tracheae were badly seen. They appeared to divide dichotomously into curved, but 

 not waved branchlets. 



In the larva of Lampyris they were long, waved, and either branched dichotomously, or 

 gave off little branchlets at intervals, very much, in fact, as on the stomach and ilium. 

 In Necropliorus vespillo and N. Immator the l)ranchlets were more numerous, so as to have 

 almost the appearance of being in tufts. They are less wavy than in Bampyris. In Carabiis, 

 Cerambyx moschatus, Ampliimalla solstitialis, Ifelolontha vulgaris, and Bucanus cervus, 

 the ends of the tracheae when examined were filled with fluid, and therefore could no 

 longer be distingtiished. 



