42 



hairy covering, which Westring believes himself to have found 

 between them (for inst. the presence of vertical hairs on the meta- 

 tarsi of T. extensa and their absence in T. obtusa) may , as is rightly 

 remarked by Menge , be found between different individuals of either 

 form. Moreover in the relative length of the spines on the legs a 

 transition from the one form to the other is often visible. On these 

 grounds I cannot consider T. obtusa as a species different from T. ex- 

 tensa: if two or more species be confounded under this latter name, 

 they must be distinguished by quite other characters than those 

 mentioned by Westring and Menge. 



The form of the abdomen varies greatly, especially with age. 

 I have a young female specimen (about 4'/ 2 min - long), where it is 

 very high and arched, and the length to the breadth in about the 

 proportion of 7 to 5. In young specimens also the cephalothorax , the 

 extremities and the parts of the mouth, especially the mandibles, 

 are somewhat shorter than in fullgrown individuals, but the spines 

 on the legs are proportionately longer. In fullgrown ^ -individuals 

 the legs are sometimes 7 times, sometimes only 6 times, but in 

 the male usually about 8 times as long as the cephalothorax. The 

 metatarsus (1 st pair) I found in a Q to be 5 times, but in a cT 

 only 4 times as long as the tarsus. All this applies to specimens 

 of T. extensa Westr. 



The distance between the lateral eyes is always something 

 less than between the anterior and posterior central eyes, and the 

 two rows of eyes are accordingly somewhat, though slightly, con- 

 vergent at their extremities. By this criterion the species is imme- 

 diately distinguished from T. striata L. Koch ') , in which the side- 

 eyes are more widely separated, so that the two rows diverge at 

 their extremities. Of that species, which has considerably shorter 

 legs (in 9 only 5 times the length of the cephalothorax) and a 

 totally different form of the mandibles from that of T. externa, 

 Dr. Haglund has found two young specimens in Ostergotland. These 

 specimens have still coarser extremities than a fullgrown female of 

 1\ striata, with which Dr. L. Koch kindly presented me: the meta- 

 tarsus of the larger specimen (a young cf) is but little more than 

 twice the length of the tarsus (in the adult ? it is nearly 3 times 

 as long as the tarsus). This species had been previously found (by 

 L. Koch) only at the lake of Wiirm or Starenberg in Bavaria. 



1) Zur Arachniden-gattung Tetragnatha , loc. cit. 



