the segmental ring of Spirobolus consists? of sixteen selerites; twelve 

 dorsal, two pleural and two ventral or pedigerous laminae. It will be 

 seen that only the last tend to indicate a transverse division of the 

 sei_MiH -in. and in no Diplopod as yet has there been shown a transverse 

 suture carried around the segment and dividing it into two parts. 

 Only the legs and the parts necessarily connected with them, such as 

 the pedigerous lamina? and nerve ganglia are duplicated. Even in the 

 Oniscomorpha, Limaeomorpha and Colobognatha where the pleura' are 

 mo<t distinct, there is not the slightest indication that they were ever 

 divided, and as they are the elements to which the pedigerous laminae 

 are next related, their evidence is more important than any drawn 

 from the dorsal parts of the segment. 



There is another way. however, in which a diplopodous animal might 

 be developed from a monopodous ancestor. Alternate segments may- 

 have been suppressed, while the corresponding legs have been pre- 

 served. For such a supposition we have the analogy of the Chilopoda, 

 where the pedigerous segments alternate with more or less rudimentary 

 segments. In this case, however, the legs have been lost, that is, we 

 must suppose so if we claim the analogy. Such a theory, while no 

 more fantastic than the other, is probably no nearer the truth. After 

 theoretical explanations have been exhausted we may. perhap-. learn 

 that the double-footed condition is a peculiarity of this group of ani- 

 mals not explainable by any general morphological considerations, but 

 sui qeneris, after the manner of the branched segmental appendages of 

 the Crustacea. — O. F.Cook. 



Secretion of Potassium Hydroxide.— Mr. O. H. Lalter has 



that the imagines of eight species secrete from the mouth an alkaline 

 fluid on emerging from the pupa. The three species of Dicntnuw 

 wear what is railed a shield, derived from the pupa ease as they emerge, 

 and thev Mih-«M,u,-iitIy remove it by their legs. He finds that the 

 strength of the solution in D. rinnla is about 1.4 grm. of potassium 

 hydroxide in every 100 ccm. of liquid. The mesenteron of the same 

 species develops an anterior dorsal diverticulum for storage of the 

 alkali during pupal life.— Journal Royal Mic. Society. 



Lake Superior Coleoptera.— 

 an admirable list of Coleoptera from 



i Tram Ent. Soc. Lond.. 1895, 399-312 



3 Proc. Davenport Acad. Nat. >. ien, > . 



