311 



over is considerably larger. Full-grown Specimens of 2\ fabrilis (as 

 also of the real T. inquilina) always have the belly black, which is 

 on the contrary never the case with C. Koch's L. inquilina. — Koch's 

 figure 1392 seems however to represent a young T. fabrilis (Clerck). 



Of T. fabrilis Ohl., Ohlebt has favoured me with specimens, 

 belonging to 1\ fabrilis (Clerck). I have myself caught T. fabrilis 

 (Clerck) in Germany, at Pyrmont. — Full-grown specimens of both 

 sexes of T. inquilina (Clerck) from Bavaria have been sent me by 

 L. Koch under the name of L. fabrilis C. Koch. 



A careful reading of the descriptions of T. fabrilis and T. in- 

 quilina, given in Rec. crit. Aran. (p. 41, 44) and in Westring's 

 Aran. Suec. (p. 505, 507), might probably prevent all farther con- 

 founding of these two species. They have also been correctly distin- 

 guished by Zimmermann loc. cit. It may suffice here to state, that 

 the normal marking on the upper part of T. inquilina (Clerck) is 

 just such as C. Koch has represented it loc. cit., figg. 1389 (cf) 

 and 1390 (9). The marking on the back of the abdomen of T. 

 inquilina (Clerck) is frequently very indistinct, especially in the 

 male, where the back along the middle is often of a uniform red- 

 dish grey colour, only with two small black spots in front (just 

 such a cf jun. is Ar. nivalis Clerck). Both in 3 and $ of T. fa- 

 brilis (Clerck) on the other hand, the spear-shaped spot on the an- 

 terior part of the abdomen is always plainly visible, and the lateral 

 bands on the cephalothorax are always paler and more sharply de- 

 fined than in T. inquilina. The female T. fabrilis has along the 

 middle of the pars cephalica a fine, brown, double line, which in T. 

 inquilina is usually, if not always, absent. In the former species the 

 mandibles are longer, in T. inquilina $ shorter, than the metatarsi 

 of the 1 st pair. The vulva in T. fabrilis consists af a narrow, ob- 

 long fovea, with a narrow and low septum at the bottom; imme- 

 diately behind that fovea is a broader transverse costa, dilated in front 

 into a short angle united with the septum. The male's bulbus geni- 

 talis has, beneath, on the outer side, a strongly compressed, lamellar 

 process, which is higher inward, and which, on its anterior surface, 

 bears a lamellar, broadly truncated tooth ; viewed from within and 

 from behind, this process has the form of a tooth slightly cloven at 

 the apex, with pointed branches; viewed from the outer side, it is 

 pretty much like a coarse tooth bent forwards into a right angle. 

 In T. inquilina c? we find at the same place only a low, simple, 

 short lamella or compressed tooth, directed obliquely inwards, which 



