Dugesiella bentzi (Girard). 357 



anatomy differs in many respects from that of tlie triie spiders and 

 tliey may be regarded as a phylog-enetically older group connected 

 with the palaeozoic spiders throngh tlie family Liphistüdae, represen- 

 tatives of wliich are known from Pinang and Sumatra. We find 

 among the Theraphosids wonderful cases of adaptation and a great 

 diversity of fornis and instincts, but their study requires a thorough 

 knowledge of the Avhole group as well as of the different species 

 and their characters, since there are few animals which are more 

 difficult of Identification. Very few species can be identified off'hand 

 and then. only when the locality is well known. The majority 

 require minute examination under the microscope, combined with 

 careful measurements, a procedure of course possible only on dead 

 specimens. Extreme caution is advisable in procuring material, in 

 Order to make sure that all individuals belong really to the same 

 species. The actual handling of even the largest, so-called „Taran- 

 tulas" (name given in America to Aviculariidsj, is very simple and 

 safe since they are peaceful and rather sluggish creatures. 



There exists a remarkable parallelism between the Theraphosids 

 and the true spiders, both in regard to their structure and habits. 

 The „tarantulae" dig holes in the ground or live under rocks or 

 logs, just as we find among the Lycosidae. The wonderful trapdoor 

 nest of the Ctenizidae has its parallel in the turrets of some American 

 and European Lycosidae. quite especially the Lycosa singoriensis and 

 Lycosa opifex, the latter of which, according to Professor Wagner 

 who has given a detailed description of the species and its habits, 

 makes a genuine trapdoor. The IscJmoihelidae make webs similar to 

 those of the common Agelena and are grey in color with long 

 spinnerets and rapid in their motions. During my trip to Mexico I 

 saw a great many webs of Evagrus mexicanus and Ischnothele digüata 

 among the aloe and other plants in the vicinity of Vera Cruz and 

 did not at first pay any attention to them, thinking that they were 

 webs of Agelena naevia. Not until my attention was attracted by 

 the unusual size of one of these webs, did I discover that every 

 one of them contained a Theraphosid and not a true spider. These 

 spiders, also, sit in the depths of the tubes of their webs, hurling 

 themselves with lightning-like rapidity upon any insect that falls 

 into the snare and hurrying back with it into the tube. They are, 

 moreover, daylight creatures and not afraid even of the tropical sun 

 at noon. It is interesting also to mention that I frequently found 

 in the tropical jungles of Central America one or two males of 



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