18 Mr. T. V. WoUaston on undescribed Madeiran Insects, 



Fig. 23. Docidium truncatum ; an individual about to divide, treated with 

 solution of carbonate of ammonia. 



Fig. 24. Recently-divided individual of the same species, laid in glycerine. 

 The protruded new membrane of one half (the contents of which 

 are drawn) has become doubled-in by the action of thefluid extract- 

 ing water. The thin, gelatinous envelope which surrounded the 

 old halves appears more clearly than in specimens lying in water. 



Fig. 25. One-half of a similar object, treated with carbonate of ammonia. 

 Only the outlines of the contracted cell-contents are given. 



Figs. 26, 27. Globular cells surrounded by a double coat, occurring fre- 

 quently among small Desmidieae, after having been kept a long 

 time in glycerine. 



Fig. 28. One of the same with a simple coat ; a fresh specimen. 



Fig. 29. Two cells produced by the division of one of these cells, adhering 

 together at the flattened surface of contact. 



Fig. 30. Outline sketch of a Cosmarium margaritiferum beginning to 

 divide. 



Fig. 30 b. The isthmus of this cell more magnified. 



Fig. 31. Navicula viridis at the commencement of division. 



Figs. 32, 33. The same plant in more advanced stages of division. The 

 stria? of the primary sides, indications of which were already 

 visible, in fig. 33, in the newly-formed adjacent sides of the 

 daughter-cells, are omitted, in order to leave the drawing clearer. 



II. — Brief Diagnostic Characters of undescribed Madeiran Insects. 

 By T. Vernon Wollaston, M.A., F.L.S. 



[With two Plates.] 



Ordo COLEOPTERA. 



Pam. CARABID^. 



Genus CALATHtJS, Bon. 



Calathtis fimbriatus. 



C. apterus, latiusculus, C. complanato plerumque paulo brevier, 

 valde depressus, piceus, prothorace latiusculo, antennis pedibusque 

 ferrugineis. 



Mas nitidus ; tibiis posterioribus intus (prsesertim versus api- 

 cem) pilis longis densissime fimbriatis. 



Foem. opacus ; tibiis fere simplicibus. 



Calathus complanatuSt var. y, Ins. Mad. 30 (1854). 



Inhabits Porto Santo, abounding beneath stones (principally 

 in the lower districts), and being apparently the Porto-Santan 

 representative of the C. complanatus of Madeira proper and the 

 Dezertas. Although attention was called, in the ' Insecta Ma- 

 derensia,' to the present Calathus — as being considerably flatter, 

 and rather broader and shorter than the ordinary C. complanatus 



