. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 488 IN VERTEBRA TE MORPUOLOO Y. they do upon vej,'etable food either in the adult or larval stages, aud occurriug occasionally iu enormous numbers, form powerful enemies to the horticulturist and agriculturist, the Eocky Mountain Locust, for example, devastating at times the crops, while fruit and forest trees are injured by the at- tacks of other forms. The Insecta differ from other Tracheata iu having the body divided into three well-marked regions. The most an- terio
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 488 IN VERTEBRA TE MORPUOLOO Y. they do upon vej,'etable food either in the adult or larval stages, aud occurriug occasionally iu enormous numbers, form powerful enemies to the horticulturist and agriculturist, the Eocky Mountain Locust, for example, devastating at times the crops, while fruit and forest trees are injured by the at- tacks of other forms. The Insecta differ from other Tracheata iu having the body divided into three well-marked regions. The most an- terior of these is the unsegmented head, bearing the autenuio and the masticatory appendages, and immediately following it is the thorax, composed of three segments, the prothorax, mesothorax, and metaihorax, each of the last two bearing usually a pair of wings upon its dorsal surface, while pos- teriorly is the segmented abdomen composed typically of ten segments, sometimes as broad as the thorax at the junction with that region, sometimes contracted to a narrow stalk. In many cases, however, the apparent number of segments falls below ten owing to the fusion of certain of the posterior seg- ments or the union of the anterior segment with the thorax, and in the Butterflies and two-winged Flies the thoracic seg- ments seem to be reduced to two owing to the close associii- tion of the metathorax with the first abdominal segment. Four pairs of appendages are borne by the head. The autenme, and indeed all the appendages, vary greatly in shape in the various groups, but are usually long slender raultiarticulate structures i)r()vided with sensory hairs. The masticatvry appendages are a pair of mandibles aud two pairs of maxilla", which are variously specialized for bitinj,', l)iercing, or sucking. The most typical condition is that iii which the entire apj)aratuH is adapted for biting and that niav be described here, leaving special modifications to bo con- sidered in connection w
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1896
