180 MICHIGAN SURVEY, 1908. 



"Collections made at Laredo, San Diego, Corpus Christi and in the lower Nueces 

 river valley prove that, with few exceptions, no tropical forms occur in that section, 

 and the trip on the stage from Alice to Brownsville shows that the character of 

 the country does not change southward until the black alluvial soil of the delta 

 of the Rio Grande is reached. Here, within the bends of the river, as well as 

 along the various backwaters and old river arms (resocas) which dissect the delta, 

 isolated areas or strips of larger or smaller extent are covered with a dense forest 

 having thick undergrowth of varied shrubbery and a rich vegetation of lower 

 plants, the like of which is not seen at any other place in Southwestern Texas. 

 The forest jungles (in Florida they would be called hammocks) are the home 

 of the semitropical insect fauna of Texas, which, so far as known to me, has, 

 previous to the year 1895, never been investigated by any entomologist, since even 

 many of the most abundant species are either entirely new or not yet recorded 

 from the United States. If, confining myself to Coleoptera found by Prof. Town- 

 send or myself near Brownsville, I mention the genera Agra, Dasydactylus, Phys- 

 orhinus, Achryson, Qnaphalodes, Amphionycha, Megascelis, Plectrotreta, Brachy- 

 coryne, Listronychus, Polyuria (quite a number of others are not yet determined, 

 or undescribed), no one can deny the existence of a semitropical insect fauna along 

 the north bank of the lower Rio Grande. The number of species composing this 

 fauna is very large; in Coleoptera alone I estimate that, after proper exploration, 

 between 300 and 400 species will be added to our lists. 



As stated above, these semitropical thickets occur in isolated patches in the 

 lowest parts of the delta; wherever the ground is a little more elevated, the usual 

 mesquite and spiny chaparral, liberally interspersed with Opuntias, make their 

 appearance, and with ihem the general fauna of southwestern Texas." 



Soudder, 1895. pp. 27-28. 



"The Post-pliocene deposits have proved the most prolific with thirty-two species, 

 though here only seven families are represented, of which the Carabidae and 

 Staphylinidae, but especially the former, very largely predominate. The greatest 

 interest attaches to the interglacial locality near Scarboro', Ont., which alone has 

 yielded twenty-nine species,* and is the largest assemblage of insects ever found 

 in such a deposit anywhere. These clays have been studied and their fossils col- 

 lected by Dr. G. J. Hinde.t who sets forth the reasons why he regards them as 

 interglacial, lying as they do upon a morainal till of a special character and over- 

 lain by till of a distinct kind. The elytra and other parts of beetles found by him 

 represent five families and fifteen genera; they are largely Carabidae, there being 

 half-a-dozen species each of Platynus and Pterostichus, and species also of Patro- 

 bus, Bembidium, Loricera and Elaphrus. 



The next family in importance is the Staphylinidae, of which there are five 

 genera, Geodromicus, Arpedium, Bledius, Oxyporus and Lathrobium, each with a 

 single species. Hydrophilldae are represented by Hydrochus and Helophorus, each 

 with one species, and the Chrysomelidae by two species of Donacia. Finally a 

 species of Scolytidae must have made the borings under the bark of a juniper 

 described below. 



"Looking^at the assemblage of forms as a whole and noting the distribution of 

 the species to which they seem to be most nearly related, they are plainly indigen- 

 ous to the soil, but would perhaps be thought to have come from a somewhat more 

 northern locality than that in which they were found; not one of them can be 

 referred to existing species, but the nearest allies of not a few of them are to be 

 sought in the Lake Superior and Hudson Bay region, while the larger part are in- 

 habitants of Canada and the northern United States, or the general district in 

 which the deposit occurs. In no single instance 'have any special affinities been 

 found with any characteristically southern form, though several are most nearly 

 allied to species found there as well as in the north. A few seem to be most nearly 

 related to Pacific forms, such as the Elaphrus and one each of the species of 

 Platynus and Pterostichus. On the whole, the fauna has a boreal aspect, though 

 by no means so decidedly boreal as one would anticipate under the circumstances." 

 pp. 27-28. Cf. Scudder '94. 



Vlke, H. 1902. p. 3. 



"The appearance of northern and southern forms are here controlled [Wash- 



"*This statement includes four species (Hydrochus amictus, Helophorus rigescens, Pterostichus dor- 

 mitans, and Bembidium tragmentum) , found by Dr. Hinde near Cleveland, Ohio, on the shores of Lake 

 Erie, in clay beds very similar to those found near Scarboro', on the shores of Lake Ontario, but not 

 found at Scarboro' itself. They undoubtedly belong to the same category." 



" tCan. Journ, Sc, N. S., xv, 388-413 (1887)." 



