ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 239 



evident. E. Lelievre * has observed a scent in images of both sexes of 

 Thais polyxena which had freshly emerged from the pupae ; the liquid 

 which adhered to the fingers when the insdcts were touched had 

 rather the odour of the Aristolochice, the plants on which the larva 

 feeds, than that of musk. Spilosoma fuliginosa also has a scent which 

 resembles that of the Zi/goence. 



"Houses" of the Larvae of the Trichoptera.f — We have here a 

 translation into German from the Portuguese of Dr. Fritz Miiller, 

 who commences by pointing out that the order of the Trichoptera is 

 doubly interesting, from a genealogical, as well as from a biological, 

 point of view. They have much the same relation to the Lepidoptera 

 as the anthromorphous apes have to man ; it is in the highest degree 

 probable that the Lepidoptera were derived from some extinct 

 Trichopteron, or, at any rate, that the two orders arose from a common 

 stem-form, from which the inconspicuous Trichoptera have slightly, 

 and the highly coloured Lepidoptera have greatly, diverged. 



Nothing appears to be known as to the natural history of any 

 extra-European forms ; with the habitations of the separate families 

 we must deal very briefly. 



(1) The Ehyacophilidfe have their covering always so arranged as 

 to allow of the passage through it of a stream of fresh water, which 

 is necessary for the respiration of the contained larvfe. 



(2) The Hydropsychida3 form tubular houses of some kind ; the 

 larva lives in a kind of canal or passage, covered by loosely attached 

 stones ; when the larva is about to pass into the pupa-stage the 

 stones that form the house are more firmly built together. 



(3) The Leptoceridae all have movable "houses," which are 

 nearly always in the form of narrow, conical, somewhat curved tubes. 

 The larvae differ much in the material which they use, and in the way 

 in which they fix its parts and close it, when they are about to 

 become pupee. 



(4) The SericostomidEe have, as is well known, heliciform cases. 

 (6) The Hydroptilidae present some variations among themselves ; 



in addition to the two forms classified by Willoughby (1710) as 

 (a) " immobili sen lapidibus affixa," or (h) " mobili aut portatili, 

 migratoria," there is here a third, " theca lapidibus af&xa, mobili." 



The coverings of certain species of indefinite systematic position, 

 are also described, and in an appendix the author enters into a con- 

 sideration of the systematic characters of the different groups, in 

 which he takes for his basis the classification of Mr. Maclachlan. 

 The paper being essentially one of elaborate details, we must refer to 

 it for fuller information ; it is illustrated by thirty-nine figures in 

 two plates. 



y. Arachnida. 



Blastoderm of the Aranema.+ — M. Sabatier states that shortly 

 after oviposition the ovum of these Arachnida is covered by a 



* Cf. also 'Le Natm-aliste,' June 1st, 1880. 



t Zeitschr. wiss. ZooL, xxxv. (1880) pp. 47-88 (2 plaX 



$ Comptes Rendus, xcii. (1881) pp. 200-i^. 



S2 



