164 MR. r. M. CAMPBELL ON THE 



in the same position the next morning (7th August, 7 a.m.)- 

 A 10 A.M. he became restless, and wandered, with spinnerets ex- 

 tended, about the bottle, returning every now and then to place 

 his palpi on the female. After each such occasion he jerked his 

 abdomen upwards and downwards, a mo ^^ement* which I have 

 often noticed in males, both mature aud immature, and which 

 gives the idea of an expression of impatience. I was called 

 away for a few minutes, and on returning found th.e male about 

 two inches behind the female, standing as it were on tip-toe. 

 The palpi were now placed alternately and nervously to the 

 maxillae. On their removal the whole body was raised still 

 higher, and the abdomen brought nearly to a right angle with 

 the cephalothorax, with considerable muscular effort in the basal 

 portion and with violent tremulations. The movements, which 

 were repeated four times, had the effect of throwing the spider 

 slightly forward, while the palpi were shaken in that peculiar 

 manner which denotes great muscular tension in some other part 

 than that in visible motion. The palpi were now (generally 

 alternately) placed under the sternum, and moved backwards and 

 forwards, upwards and downwards with a scooping motion. In 

 five minutes these movements of the abdomen and palpi were 

 repeated ten times in regular succession, only varied by an occa- 

 sional transfer of the digital organs to the mouth. It was only 

 during the last moments of the process that reflected light en- 

 abled me to see a triangular silken sheet attached to the spider 

 behind the abdominal sexual organ by its apex, and by its external 

 angles to the mesh across the bottle. The sheet extended from 

 under the abdomen to the anterior part of the sternum and lay 

 above the palpi. The male now left the sheet and approached 

 the female ; but she appeared mindless of his addresses. I now 

 seized him ; and in his attempts to evade capture he injured the 

 silken sheet. An examination showed that the sides consisted of 

 many shreds (fig. 19, A), while the intervening space was covered 

 with an irregular mesh (fig. 20, natural size), which was doubtless 

 originally more systematically arranged. Here and there was a 

 mass of semen containing a fine granulated substance (fig. 19, B) 

 of great refractive power. The whole was in a very liquid state, 

 and spermatozoa were arranged singly above the threads. 



* This suggests one of the causes of the development of the abdominal and 



, thoracic stridulating organs in cei'tain species. See Joiuni. Linn. Soc, ZooL, 



" On supposed Stridulating Organs of Steatoda guttata, Wider.," p. 152, vol. xv. 



