. Insect life; an introduction to nature study and a guide for teachers, students and others interested in out-of-door life. Entomology; Nature study. 54 INSECT LIFE. crabs. Crayfishes (Fig. 23) abound in our brooks, and are often improperly called crabs. The lob- sters, the shrimps, and the true crabs live in- salt water. The Crustacea are distinguished from all other Arthro- pods by having two pairs of antennae and by their mode of respiration, being the only ones that breathe by true gills. Many insects live in water and are furnished with gill- like organs, but these are tracheal gills. Tr
. Insect life; an introduction to nature study and a guide for teachers, students and others interested in out-of-door life. Entomology; Nature study. 54 INSECT LIFE. crabs. Crayfishes (Fig. 23) abound in our brooks, and are often improperly called crabs. The lob- sters, the shrimps, and the true crabs live in- salt water. The Crustacea are distinguished from all other Arthro- pods by having two pairs of antennae and by their mode of respiration, being the only ones that breathe by true gills. Many insects live in water and are furnished with gill- like organs, but these are tracheal gills. True gills are for the purification of blood, while tracheal gills are for the purification of the air con- tained in the air ves- sels or tracheas of an insect. The former contains a large num- ber of blood Fig. 23.—A 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 Comstock, John Henry, 1849-1931; Comstock, Anna Botsford, 1854-1930. New York, D. Appleton and Company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomol, bookyear1901
