254 MR. F. PICKARD CAMBRIDGE ON THE [Apr. 1 5, 



5. Latrodectus cuRAgAviENSis (Mliller), 1776. (Plate XXYII. 



fig. 4.) (Sub-species.) 



Synonym. L. geographicus, Van Hasselt. 



The two females, referred by M. Simon to the former name, 

 from Asuncion, and kindly lent me for examination, are adult, 

 and represent a type of coloration often found in the immature 

 of L. mactans. This form has the abdomen mainly red, with a 

 pair of parallel black longitudinal bands posteriorly, and two or 

 more transvei'se black cinctxu-es anteriorly. The type of coloration 

 is the same as that of some males and females which I took on 

 the sandy campos near Santarem, on the Lower Amazons ; and 

 the latter are unmistakably like Van Hasselt's figure of L. geo- 

 graphicus, though the precise form of the coloration differs. 



But, in this case again, though the Spiders ai'e veiy much 

 smaller, I am unable to find any really I'eliable difference in the 

 papal organs or in the vulva from those of L. mactans. Difierences 

 may indeed exist, and possibly with several dozen examples to 

 compare, instead of two or three, one might find them. 



At present, however, I can only regai'd this form as a dwarf 

 race with difierent form of colora,tion, and for the time being 

 must consider it as a sub-species. 



Hah. OuRAgoA, West Indies (MilUer) ; Paraguay : Asuncion, 

 San Pedro and Rio Apa (Simon) ; Surinam ( Van Hasselt) ; 

 Amazons {F. Cambridge). 



6. Latrodectus tredecim-guttatus (Rossi), 1790. (Plate XXVI. 



fig. 3.) (Sub-species.) 



Synonyms. L. mahnignatus Walck, — L. m.artius Aud. in Sav. 

 — L. argus Aud. in Sav.-^Z. venator Aud. in Sav. — L. 

 erebus Walck. — L. luguhre (Dufour, sub Theridion). — L. 

 oculatus Walck. — L. conglobatus 0. L. Koch. — Z. lugubris 

 Motsch. — L. hispida (0. L. Koch), sub Meta. 



This is perhaps the best known form, being common all through 

 the South of Europe, the Meditei'ranean region, Northern Africa, 

 and through South Russia and Syiia. It is notorious in all parts 

 of this region for its venomous bite. 



The only real distinction I can find between the ^^ forma prin- 

 cipalis " of 1 B-guttatiis and _ mactans is that in the female the 

 lateral anterior eyes are fui-ther from the centiuls than these are 

 from each .other, and the haiiy clothing is much finei'. In the 

 maZes, . however, there is no difference in this respect. This 

 character (the eye-formula), moi'eover, is not constant in the 

 females of either mactans, tredeci'ni-guttatus, or hasseltii. I can 

 find no tangible dijfference between the various parts of the 

 palpal organs in the male, or of the vulva in the female, of these 

 forms {hasseltii S is unknown to me). 



I believe these to be aU ofi^shoots of one original form, for which 

 the. oldest name is mactans. . 



Hah. Europe : Spain, Italy {Walck.) ; Greece {C. L. Koch) ;— 



