130 



CRABS AND INSECTS. 



deposited on the water, and the larvaa breathe by a star- 

 shaped organ at the hinder extremity, through which air 

 passes to the tracheae. They finally shed their skins and 



appear as pupae, in which state 

 they breathe through two tubes 

 in the thorax. In a few days 

 the skin breaks between the 

 breathing-tubes and the insect 

 emerges, and, after floating 

 about for a while on the old 

 skin as a raft, it flies away a 

 perfect insect. 



FIG. 163. Antenna of mos- 

 quito, magnified. 



NOTE. In the small town of Elizabethport, Russia, in the month 

 of June, 1830, 30 horses, 40 foals, 70 oxen, 90 calves, 150 hogs, and 

 400 sheep were killed by mosquitoes alone. The females generally do 

 the most damage. 



Works on Diptera for further reference. 



" Transformations of the Common 

 House-Fly, with Notes on Allied Forms," 

 A. S. Packard, Jr., " Proceedings of the 

 Boston Society of Natural History," vol. 

 xv ; "Catalogue of Described Diptera of 

 North America," R. Osten-Sacken, in 

 "Smithsonian Miscellaneous Collections," 

 vol. iii, No. I, 1862 ; " Animal Parasites 

 and Messmates," Van Beneden. 



Order VII. Butterflies and 

 Moths (Lepidoptera). General 

 Characteristics. Small-headed in- 

 sects with four wings, which with the 

 body are covered with scales ; the 

 tongue consisting of two tubular or 

 hollow threads adapted for suction, 

 and coiled when not in use ; meta- 

 morphosis complete, the larvae or 

 caterpillars-having abdominal legs. 



FIG. 164. Head of 

 Sphinx - moth, show- 

 ing coiled tongue, and 

 pollen-masses that have 

 been taken from some 

 flower, attached to the 

 eyes. 



