. A manual of zoology. Zoology. 474.—Sirex gigas, saw Sy (after Taschenberg). exceeds the (>thcr thoracic somites, so that these, especially the prothorax, seem but parts of the strong mesothorax. Besides, the first abdominal ring unites to the thorax so intimately in the Entophaga and Aculeata as to seem part of it. The constriction which then separates thorax and abdo- men comes between the first and second abdominal somites, and when the second (petiole) is elongate the stalked abdomen, familiar in the wasps, results. The sexes are distinguished by the genital armature. The female is pro
. A manual of zoology. Zoology. 474.—Sirex gigas, saw Sy (after Taschenberg). exceeds the (>thcr thoracic somites, so that these, especially the prothorax, seem but parts of the strong mesothorax. Besides, the first abdominal ring unites to the thorax so intimately in the Entophaga and Aculeata as to seem part of it. The constriction which then separates thorax and abdo- men comes between the first and second abdominal somites, and when the second (petiole) is elongate the stalked abdomen, familiar in the wasps, results. The sexes are distinguished by the genital armature. The female is pro- vided with the ovipositor already de- scribed (p. 413), which when used for this purpose only (terebra) permanently projects from the hinder end of the body (fig. 474), but when used as a sting {aculeus), can be drawn into the body when at rest. The sting, naturally lack- ing in the male, is connected with a poison gland, the secretion of which owes its effect not, as once Ijelieved, to formic acid, but to a little known basic substance, possibly secreted in smaller accessory glands. The distinction between terebra and aculeus affords characters of system- atic importance; others are furnished by the development, which is always holometabolous. The pupas, in all important points, are similar (pupa; liberae), but two kinds of larvae are distinguished. Some have well-developed lef;s. Others have footless larvs (fig. 60). The first occur where the larva must shift for itself, the second where it is surrounded by an abun- dance of food, either provided by the parents or by the hojt in which it is parasitic. Sub Order I. TEI^EBRANTIA. Terebra present; larvse with feet at least on the thorax; eggs laid on leaves or in wood, usually without gall formation; the larvae therefore must move in order to feed. , saw flies, feed on leaves, larvas caterpillar-like. Cimbex* Ncmalus* Siricid,<e (Urocerida;, fig. 474), horn tails, larvos bore in wood. Sub Order II. ENTOPHAG.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
