MARYLAND GEOLOGICAL SURVEY 171 



Of those that are aquatic in habits the greater number are confined to 

 the smaller ponds and lakes, or if they occur in larger bodies of water 

 they usually remain near the shores where the accumulating sediment is 

 either of coarse texture or temporary. The chitinous skeleton of the in- 

 sect is not well adapted for the rough tossing of waves. The body is often 

 taken as food by the various predatory inhabitants of the water and the 

 wings are delicate and require a fine grained matrix for their preserva- 

 tion. A partial exception to these statements is presented by the Col- 

 eoptera, or beetles, which have a thickened and resistant front wing admit- 

 ting of preservation in sediments in which the more delicate wings of 

 other insects are rarely found. 



The Coleoptera are not known from deposits older than the Triassic, 

 the several indefinite fossils recorded from Paleozoic rocks referred to 

 this order proving one after another, to belong to some other 

 order. Among the most frequently quoted evidence of Coleoptera in 

 Paleozoic time is the boring in wood from the Carboniferous of Altenwald, 

 Germany, described in 1877 by Charles Brongniart as borings of Scoly- 

 tidse and referred provisionally to the genus Hylesinus. In his final 

 monograph on paleozoic insects, however, (Insectes fossiles, p. 452, 1893) 

 Brongniart states in reference to the perforated wood : " En 1877 j'ai 

 fait connaitre des bois fossiles silicifies, provenant du houiller d'Autun 

 et qui offraient des perforations regulieres que j'avais regardes comme 

 ayant ete produites par un Coleopere du genre Hylesinus. Mais rien ne 

 vient confirmer cette assertion, car aucune empreinte authentique de 

 Coleopere n'a ete decouverte et les imprintes qui ont ete decrites comme 

 telles ne sont autre chose que des graines fossiles, ou bien ont ete at- 

 tributes a des arachnides de groupe des Antliracomarti." The Troxites 

 Germari of G-oldenberg has with closer study been considered a fossil 

 fruit. Dipeltis, sometimes doubtfully referred to the Coleoptera (Zittel, 

 Text-Book of Paleontology, Eastman's translation, p. 687) has been 

 shown by the writer to be the larva of a cockroach (American Journal of 

 Science, Vol. XV, p. 309, 1903). 



Among the Pleistocene material from Anne Arundel County occasional 

 remains of Coleoptera are found, most of which consists of carbonized 



