240 



SCIENCE-GOSSIP. 



specific characters. Such drawings should include the 

 palpus of the male with its appendages, the vulva of 

 the female, and the eyes and fakes viewed from in 

 front. 



I should strongly advise students of this Order to 

 obtain a copy of "The Spiders of Dorset," and, if 

 possible, Blackwall's " Spiders of Great Britain and 

 Ireland " should be consulted for the sake of the 

 plates. These latter, although in many cases not 

 sufficiently accurate to distinguish obscure species, 

 are most useful in conjunction with the first named 

 work. 



It should be noted that in the following list of 

 spiders I have given only those characteristics neces- 

 sary for the identification of genera and species, and 

 these solely so far as the British forms are concerned. 

 When I have noted habits or localities, it is either 

 from personal experience, or from some trustworthy 

 authority. 



The measurements given are from typical specimens, 

 but all species are subject to more or less variation in 

 this respect. As before mentioned, the metric system 

 will be used, the dimensions being stated in milli- 

 metres. 



In executing my drawings, the subjects have neces- 

 sarily to be enlarged ; but in the letterpress the average 

 measurements are given of each species depicted. 



The description of the most important parts, with 

 regard to families, will be in accordance with and in 

 the same order as in my introduction {ante, page 

 194). 



Family i. THERAPHOSIDAE. 

 Most of the spiders included in this family are found 

 in tropical countries. They are usually of large size, 

 heavily and powerfully built, and very hairy. The 

 colouring is never very bright, being usually brown or 

 dark brownish-red. Many species form trap-doors at 

 the entrance to their retreats. The form of the chief 

 parts may be noted as follows : — Cephalo-thorax. 

 This is usually broad and flattened, the front portion 

 of caput being more or less raised. Eyes. These are 

 eight in number, and arranged on the front raised 

 portion of the caput. An example is shown on Fig. III. 

 One tropical genus has six eyes. Legs. Strong and 

 robust. Falces. Articulated so as to be capable of 

 movement in a vertical plane. Maxillae are long 

 and the labium usually rather small. Palpi. These 

 in the female are used as organs of locomotion. 

 Abdomen. Small compared with the cephalo-thorax. 

 The breathing organs are four in number, placed in 

 the form of a square. The spinners are six in number 

 (four in some exotic genera), the superior pair being 

 turned upwards. 



GENUS ATYPUS LATR. 

 Eyes eight, arranged as in Fig. III. (Theraphosidae), 

 Falces enormously developed. 



Atypus piceus Sulz. (A. suheri Latr. 

 and Bl.). 



The well-known British species (Fig. I.). 

 Length. Male 8.4 mm., female 13 mm. 

 Localities. Dorset, Hampstead Heath, Channel 

 Isles. 



Atypus blackwallii Sim. 



This is a Continental species, and does not appear 

 to be British. The specimen described in " Spiders 

 of Dorset" is probably a malformed male of A. piceus. 



Atypus beckii Cambr- 



This is an exceedingly rare species. It may be 

 distinguished from A. piceus by its somewhat larger 

 size and by the ocular area being longer and narrower^ 

 In colouring the two species are very similar. 



Length. Male about 9 mm., female about 14 mm. 



Localities. Portland and Hastings. 



Family 2. ERESIDAE. 



The spiders included in this family are found 

 chiefly in warm countries, but the family is a small 

 one. Only one species has been found in Britain. 

 The form of the chief parts is as follows : — 



Cephalo-thorax. Rather quadrate, the caput 

 being convex and raised above the thorax. Eyes. 

 Arranged more or less as shown in Fig. III. Legs. 

 Strong. The metatarsi of the fourth pair are calamis- 

 trated in the female. Falces. Rather small, capable 

 of a horizontal movement. Maxillae. Rather 

 straight, labium somewhat elongated. Palpi. Short 

 and thick. Abdomen. Obtuse, more or less 

 oviform. Ordinary spinners rather short. A super- 

 numerary spinner is present in both sexes. 



GENUS ERESUS WALCK. 

 Eyes eight. Arranged as shown in Fig. III. Legs 



4, I, 2, 3- 



Eresus cinnabarinus Walck. 



This spider, which is the only British representa- 

 tive of the family Eresidae, may be distinguished 

 without difficulty on account of its brilliant and beau- 

 tiful colouring. The abdomen is of a bright scarlet 

 hue, with four black spots on the upper surface. These 

 spots are of considerable size and are fringed with 

 white hairs. Unfortunately, this species is exceed- 

 ingly rare. 



Length of the male 8 mm. 



Localities. Dorset, Bournemouth, Channel Isles. 



Family 3. ULOBORIDAE. 



The spiders comprised in this family are few in 

 number, and very remarkable in both structure and 

 habits. The snare is of a more or less perfect geometric 

 form. The chief characteristics of the family may be 

 noticed as follows : — 



Cephalo-thorax. Short, oblong and depressed. 

 Eyes. The laterals of the two.rows are always well 

 separated (Fig. III.). Legs. These are strong, and 

 the first pair much the longest. ' The female has the- 

 metatarsi of the fourth pair calamistrated. Falces. 

 Moderately developed and capable of a horizontal 

 motion. Maxillae. Strong and fairly straight ; 

 labium rather short. Palpi. Highly developed in 

 the male. Abdomen. Large and projecting over 

 the thorax. Spiracular openings two in number. A 

 supernumerary spinning organ is present in both 

 sexes. This family contains two British genera, easily 

 distinguishable by the position of the eyes. It 

 includes no common species. 



