. Fresh-water biology. Freshwater biology. AQUATIC INSECTS 90^ Many of the largest larvae are fiercely cannibalistic and will eat their brethren even when other food offers. Some of the larvae are provided with swimming fringes on the legs, some have them on the tail, and many have them in both places. Some, like the larvae of Acilius, are exceedingly lithe and graceful creatures. Others (Fig. 1377) scarcely swim at all, but creep about among the trash at the shore Fig. 1377. The larva of Coptotomus inlerrogatus. In the present state of our knowledge, it is not possible to give keys tha
. Fresh-water biology. Freshwater biology. AQUATIC INSECTS 90^ Many of the largest larvae are fiercely cannibalistic and will eat their brethren even when other food offers. Some of the larvae are provided with swimming fringes on the legs, some have them on the tail, and many have them in both places. Some, like the larvae of Acilius, are exceedingly lithe and graceful creatures. Others (Fig. 1377) scarcely swim at all, but creep about among the trash at the shore Fig. 1377. The larva of Coptotomus inlerrogatus. In the present state of our knowledge, it is not possible to give keys that will determine genera of Dytiscid larvae, and the best means of identifying native larvae is by comparison with the beau- tiful figures of Schiodte, who long ago (1861) described the European representatives of many of our genera. The Two-winged Flies (Order Diptera) Of this immense order a considerable portion has taken to a more or less aquatic life. A majority of the famihes have some members that develop in the water, but only a few of the smaller famihes are wholly aquatic. Those best fitted for hfe in the water show adaptations of the most diverse sorts, so that here again the families are best considered separately. Since nearly all the families of the Diptera have some aquatic members, the determination of the adult flies must be left to the aid of the keys in the entomological manuals that are everj^where avail- able. Each of these families has a characteristic type of wing ven- ation, and some aid may be had from comparison with the typical wings shown in Fig. 1378. It is quite impossible in the space at command to give keys to the genera of Dipterous families, these being very numerous. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ward, Henry Baldwin, 1865-1945; Whipple, George Chandler, 1866
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
