402 Annals Entomological Society of America [Vol. IX, 



six vessels associated with the wall of the colon. However, 

 the distribution of these vessels in the colon wall of Galerucella, 

 according to 'Poyarkoff, is very similar to the alder flea beetle. 

 In Galerucella they are at first small, and then they become 

 larger, ramifying irregularly so as to form an almost complete 

 layer around the canal. In his figures, the peritoneal envelope 

 is shown passing around the Malpighian vessels and outside 

 the longitudinal muscles, just as has been described above for 

 Haltica bimarginata. 



The most recent paper dealing with the general subject 

 of Malpighian tubes is the valuable contribution of Gorka 

 in 1914. He studied two genera of Coleoptera, Gnaptor (family 

 Tenebrionidae) and Necrophorus (family Silphidae). In his 

 general summary may be found the following conclusions: 

 "The number of Malpighian vessels is six in Gnaptor spinimanus 

 and four in Necrophorus humator. In Gnaptor the Malpighian 

 vessels build a network on the walls of the rectum, yet without 

 emptying into it. Out of this network, which is due to the 

 union of the vessels in pairs after a long wavy course on the 

 walls of the rectum, a single thick stem is formed. This stem 

 does not represent a fusion of the Malpighian vessels, but only 

 a very close apposition. The common stem then divides into 

 two branches, each of which consists of three vessels. Finally 

 these also separate out and empty after a short course through 

 the body cavity into the intestine, at the boundary of the 

 mid-intestine and the hind-intestine. The Malpighian vessels 

 of Necrophorus end blindly. In all the beetles studied the 

 Malpighian vessels empty into the mid-intestine, and not into 

 the hind-intestine. A few epithelial cells follow behind the 

 insertion of the Malpighian vessels in Gnaptor, which agree 

 with the epithelial cells of the mid-intestine in every respect." 

 (Pages 330 and 331). 



Only in a very general way does this recall the condition 

 in Haltica bimarginata. In the latter the vessels do actually 

 fuse, and the two common trunks represent a real coalescence, 

 not simply a close apposition of the tubes. There is no indica- 

 tion that the trunk is composed of three distinct vessels, but 

 in cross sections it appears like an ordinary Malpighian tube, 

 and is not of an appreciably greater diameter. In Cassida, as 

 figured by Dufour (Ann. de. sci. nat. 1825, ser. 1, t. 4, pi. 8,. 



