Many species of Thysanoptera are known to be habitually parthenogenetic. The eggs are laid on the food-plant, those females possessed of an ovipositor cutting through the epidermis and placing their eggs singly within the plant-tissues; a single female may take five or six weeks to deposit all her eggs.
I, 4) the abdomen is cylindrical, the female is provided with a ventral ovipositor and has the terminal abdominal segment conical; the corresponding segment in the male is usually bluntly rounded.
There is no ovipositor, and the wings are either without nervures or have only a single degraded longitudinal nervure which does not reach to the tip. While the Terebrantia are (After H.
This flexible tube is the functional ovipositor, the typical insectan ovipositor with its three pairs of processes (see Hexapoda) being undeveloped among the Coleoptera.
The morphology of the abdomen, ovipositor and genital armature is dealt with by K.
The female lays her eggs in a slit made by means of her "saw-like" ovipositor in the leaf or fruit of a tree.
Pairs of processes carried on the eighth and ninth segments often become specialized to form the ovipositor of the female (see fig.
- Hinder Abdominal Segment and Ovipositor of Female Cockroach.
They have chiefly been studied in the female, and form the sting and ovipositor, organs peculiar to this sex.
Jointed cerci always present; ovipositor well developed.
Ovipositor usually present.
Ovipositor always well developed, and often modified into a sting.
Of special interest are cockroachlike forms, with two pairs of similar membranous wings and a long ovipositor, and gigantic insects allied to the Odonata, that measured 2 ft.
The constriction of this segment and its very perfect articulation with the propodeum give great mobility to the abdomen, so that the ovipositor or sting can be used with the greatest possible accuracy and effect.
- Ovipositor or Sting of Red Ant (Myrmica rubra) Queen.
In the different families of the Hymenoptera, there are various modifications of the ovipositor, in accord with the habits of the insects and the purposes to which the organ is put.
The sting of wasps, ants and bees is a modified ovipositor and is used for egg-laying by the fertile females, as well as for defence.
These processes are not altogether homologous with those of the ovipositor, being formed by inner and outer lobes of a pair of structures on the ninth abdominal segment.
In connexion with the ovipositor are two poison-glands, one acid and the other alkaline in its secretion.
These glands are most strongly developed when the ovipositor is modified into a sting.
Not a few cases are known in which a parasitic larva is itself pierced by the ovipositor of a " hyperparasite," and even the offspring of the latter may itself fall a victim to the attack of a " tertiary parasite."
Linnaeus divided the Hymenoptera into two sections - the Terebrantia, whose females possess a cutting or piercing ovipositor, and the Aculeata, in which the female organ is modified into a sting.
The ovipositor is long and prominent, enabling the female insect to lay her eggs in the wood of trees, where the white larvae, whose legs are excessively short, tunnel and feed.
Most saw-fly larvae devour leaves, and the beautifully serrate processes of the ovipositor are well adapted for egg-laying in plant tissues.
In this division the ovipositor issues from the ventral surface of the abdomen; the pronotum reaches back to the tegulae;.
This division resembles the Cynipoidea in the position of the ovipositor, and in the two segmented trochanters.
4, 5) and by the situation of the ovipositor just in front of the tip of the abdomen.
The ten thousand known species included in this group agree with the Cynipoidea and Chalcidoidea in the position of the ovipositor and in the jointed trochanters, but are distinguished by the fore-wing possessing a distinct stigma and usually a typical series of nervures and areolets (figs.
Guished from the pre ceding by the position of the ovipositor at the extreme apex of the abdomen, and from the groups that follow (with very few exceptions) by the jointed trochanters of the legs.
The four succeeding sections, in which the ovipositor is modified into a sting (always exserted from the tip of the abdomen) and the trochanters are with few exceptions simple, form the Aculeata of Linnaeus.
Only three or four abdominal segments are visible, the hinder segments being slender and retracted to form a telescope-like tube in which the ovipositor lies.
When the ovipositor is brought into use this tube is thrust out.
For the sting and ovipositor H.
The typical insectan ovipositor with its three pairs of processes, one pair belonging to the eighth and two pairs to the ninth abdominal segment, can be distinguished in the female.
The female, by means of her serrated ovipositor, lays her eggs in slits cut in the twigs of plants.
The exciting cause of the hypertrophy, in the case of the typical galls, appears to be a minute quantity of some irritating fluid, or virus, secreted by the female insect, and deposited with her egg in the puncture made by her ovipositor in the cortical or foliaceous parts of plants.
The cerci are nearly always joined, and a typical insectan ovipositor with its three pairs of processes is present in connexion with the vagina of the female.
The Acridiidae have the feelers and the ovipositor relatively short, and possess only three tarsal segments; their ears are situated on the first abdominal segment and the males stridulate by scraping rows of pegs on the inner aspect of the hind thigh, over the sharp edges of the forewing nervures.
The Locustidae (see Grasshopper, Katydid) have the feelers and often also the ovipositor very elongate; the foot is four-segmented; the ears are placed at the base of the foreshin and the stridulation is due to the friction of a transverse " file " beneath the base of the left forewing over a sharp ridge on the upper aspect of the right.
The genital papilla of the female acquires a great development during the breeding season and becomes produced into a tube nearly as long as the fish itself; this acts as an ovipositor by means of which the comparatively few and large eggs (3 millimetres in diameter) are introduced through the gaping valves between the branchiae of pond mussels (Unio and Anodonta), where, after being inseminated, they undergo their development, the fry leaving their host about a month later.