614 SUMMARY OF CURRENT RESEARCHES RELATING TO 



points of the leaves, through which the connecting-line passes to the 

 snare. The spider domiciles within the leafy cavern thus formed. 



Again, the spider avails herself of small holes in wood or stone, 

 openings in fences, the interspace between curled bark on the trunk 

 of old trees, or some like cavity, which she appropriates as a nesting- 

 place. 



Another variation was due to an accident in the environment of 

 the web. A colony of carpenter ants dropped their chippings on the 

 web until a ball as big as a walnut had accumulated, which was then 

 utilized by the spider as a nest, the interior being bored and silk- 

 lined. 



Other special variations are noted, including that of the nest 

 attached to exposed parts of human habitations, such as the cornices 

 of porches, outhouses, &c, and " it is thus seen that while there is a 

 general regard to protection of the spider's person, there is a modifica- 

 tion over a quite wide degree of variation in the form of the pro- 

 tective nest ; further, that this modification appears to be regulated, 

 more or less, by the accidental environment of the domicile, and in 

 such wise as to show no small degree of intelligence in adapting 

 the ordinary spinning habit to various circumstances, and to econo- 

 mizing labour and material." 



Parthenogenesis in the House Spider.* — Mr. F. Maule Campbell 

 details some interesting observations on a probable case of partheno- 

 genesis in Tegenaria guyoni, one of the females of which, after a 

 confinement of eleven months, twice moulted and afterwards laid eggs 

 which were duly hatched. This shows either that she was impreg- 

 nated previous to the casting of the two exuviae, in an early and 

 therefore immature stage, or that parthenogenesis occurs in the 

 Araneidea. Hitherto no instance of virgin production has been 

 recorded in the true spiders, though Megnin, Kramer, Haller and 

 Michael have shown that the females of some Acarina couple with 

 the males prior to their final moult, and that practically there are two 

 stages of sexual maturity. Beck and others have also related cases 

 of undoubted parthenogenesis in the Acari. 



Segmentation in the Mites."]" — P. Kramer describes the segmen- 

 tation of a minute mite, Alycus roseus. The dorsal aspect shows a 

 very distinct segmental line between thorax and abdomen. The 

 abdomen shows nine distinct segments, which follow one another 

 exactly as in Podura. The segmental grooves between the first 

 three are broad, and present somewhat the appearance of double lines, 

 of which the anterior cut off the preceding segment, and the posterior 

 commence the succeeding one. The lateral margin of the abdomen 

 shows distinctly the convexities and constrictions which correspond 

 to the middles and boundaries of the segments. The setation 

 throughout follows the segmental conditions. The hindermost 

 segment bears the perfectly terminal anal aperture, half of which 



* Journ. Linn. Soc. Lond. (Zool.) xvi. (1882) pp. 536-9. 

 t Arch. f. Naturg., xlviii. (1882) pp. 178-82 (figs.). Ann. and Mag. Nat. 

 Hist., x. (1882) pp. 183-4. 



