164 ARACHNIDES. 



are in a manner insulated by their male organs of generation, 

 by the claw or hook of their frontal mandibles, by their pedi- 

 culated abdomen and its spinning apparatus, and by their 

 habits; besides this, the Scorpions appear to form a natural 

 transition from the Arachnides Pulmonariae to the family of 

 the Pseudo-Scorpiones, or the first of the following order. 

 We will therefore commence, as we have said, with the 

 Araneides or spinners. 



FAMILY I. 



ARANEIDES. 



This family is composed of the genus Aranea, Lin., or the 

 Spiders. They have palpi resembling little feet, without a 

 forceps at the end, terminated at most in the females by a lit- 

 tle hook, and the first joint of which, in the males, gives ori- 

 gin to various and more or less complicated sexual appen- 

 dages^). Their frontal chelicerse (the mandibles of authors) 

 are terminated by a movable hook, flexed inferiorly, under- 

 neath which, and near its extremity, which is always pointed, 

 is a little opening, that allows a passage to a venomous fluid 

 contained in a gland of the preceding joint. There are never 

 more than two jaws. The ligula consists of a single piece, is 

 always external and situated between the jaws, and either more 

 or less square, triangular or semicircular. The thorax(2) 

 usually marked with a depression in the form of a V, indicating 

 the space occupied by the head, consists of a single segment, 



(1) From all the observations that have been made on the mode of copulation 

 of the Araneides, I am still inclined to believe that these appendages are the 

 genital organs. I have vainly sought for particular organs on the base of the 

 abdomen of a large male Mygale preserved in spirits. We are not always to 

 judge from analogy; for the sexual organs in the female Glomeris, Julu^, and 

 other Chilognatha, are situated near the mouth, a fact of which no second exam- 

 ple is to be found. 



(2) The term cephalo-thorax, would be more strict and proper; not being in use, 

 however, I have thought it best to avoid it; neither will I employ that of corselet, 

 although generally admitted, because, with respect to the Coleoptera, Orthoptera, 

 he. it only applies to the prothorax or first thoracic segment. 



