466 Mr. J. Blackwall on the Structure, Functions, CEconomy, 



As the Argus anticus and Argus apicatus of M. Walckenaer are 

 the same, and are identical with Walckenaera antica, I have in- 

 cluded them among the synonyma of that species, which was 

 observed on rails near Llanrwst in November 1837, and again in 

 May 1838. 



177. Walckenaera pumila . 



Walckenaera pumila, Blackw. Linn. Trans, vol. xviii. p. 639. 

 Argus pumilus, Walck. Hist. Nat. des Insect. Apt. t. iv. p. 508. 



Both sexes of this spider secrete themselves under stones in 

 moist pastures near Llanrwst. The male has the palpal organs 

 developed in May. 



' 1 78. Walckenaera picina. 



Walckenaera picina, Blackw. Linn. Trans, vol. xviii. p. 640. 

 Argus picinus, Walck. Hist. Nat. des Insect. Apt. t. iv. p. 507. 



A specimen of Walckenaera picina, captured in the neighbour- 

 hood of Manchester, was received from Mr. T. Glover in June 

 1838; and in the following month another specimen was taken 

 near Llanrwst. Both individuals were adult males. 



1 79. Walckenaera nemoralis. 



Walckenaera nemoralis, Blackw. Linn. Trans, vol. xviii. p. 641. 

 Argus nemoralis, Walck. Hist. Nat. des Insect. Apt. t. iv. p. 507. 



In March 1837 males of this species, in a state of maturity, 

 were found under stones in woods about Llanrwst. 



Genus Pachygnatha, Sund. 



180. Pachygnatha Clerckii. 



Pachygnatha Clerckii, Sund. Vet. Acad. Handl. 1829, p. 208, & 



1832, p. 258. 

 Listeri, Koch, Uebers. des Arachn. Syst. erstes Heft, p. 10; 



Die Arachn. B. xii. p. 142. tab. 430. fig. 1064. 

 Manduculus ambiguus, Blackw. Lond. and Edinb. Phil. Mag. Third 



Series, vol. hi. p. 1 1 1 ; Research, in Zool. p. 359. pi. 3. fig. 3-5. 

 Theridion maxillosum, Hahn, Die Arachn. B. ii. p. 37. tab. 53. 



fig. 122. 

 Linyphia maxillosa, Walck. Hist. Nat. des Insect. Apt. t. ii. p. 267. 

 Clerckii, Walck. Hist. Nat. des Insect. Apt. t. ii. p. 270. 



Arachn ologists, in their endeavours to identify the species con- 

 stituting the genus Pachygnatha of Prof. Sundevall, have involved 

 their synonyma in a labyrinth of such perplexing intricacy as to 

 render any attempt at revision extremely difficult. Such being 

 the case, I submit the result of a careful investigation of the sub- 

 ject to the impartial consideration of zoologists, hoping that it 



