The Brazilian solifuge Mummucia mauryi new species (Solifugae, Mummuciidae) from sand dunes of the São Francisco River, in semiarid caatinga domain, is herein described, with illustrations of the main taxonomic characters. This is the first species of Solifugae described from the Brazilian caatinga. The specimens were collected in pitfall traps during both the rainy and dry seasons. It exhibits diurnal activity and a clumped distribution (Morisita's index = 3.32 and 1.38 for rainy and dry season, respectively). Sun-exposed areas were avoided during the dry season, when preference for the cactacean Opuntia inamoena was detected. We suggest this association is related to predator avoidance.

Mundochthonius singularis, a troglomorphic species from Fly Cave in Fremont County, Colorado, is described. This is the first cavernicolous pseudoscorpion to be reported from the state. It is compared with M. montanus, the local epigean species, for which an emended description is given.

The holotype of Cecoditha parva Mello-Leitão 1939, from Chubut Province, Argentina, is redescribed and shown to be a typical member of the genus Austrochthonius Chamberlin 1929. The monotypic genus Cecoditha Mello-Leitão 1939 is therefore a junior subjective synonym of Austrochthonius, while the subfamily Cecodithinae Chamberlin & Chamberlin 1945 (Tridenchthoniidae) is a junior subjective synonym of Chthoniinae Daday 1888 (Chthoniidae).

The taxonomic status of the endemic South African flat rock scorpion, Hadogenes bicolor Purcell 1899, is reassessed, based on a study of the types and a large series of newly-collected specimens. Specimens identified as H. bicolor by previous authors can be separated into at least three species on the basis of morphology, each of which occupies a discrete, allopatric distributional range. In light of this new evidence, H. bicolor is redescribed and two new species, Hadogenes longimanus and Hadogenes newlandsi, are described. A key is provided for the identification of the three allopatric species, and their ecology and conservation status are discussed. The phylogenetic position of Hadogenes is discussed in light of a recent cladistic analysis, and the monotypic family Hadogenidae Lourenço 2000 is synonymized with the family Ischnuridae Simon 1879.

The results of a study of new scorpion material, comprising nine species collected during a recent field trip to Trinidad and Tobago, are presented. The Trinidad population of Tityus discrepans (Karsch 1879) is described as a new species, Tityus tenuicauda, endemic to Trinidad, and more closely related to Tityus arellanoparrai González-Sponga 1985 than T. discrepans, both from Venezuela. A key to the identification of the three species is provided. New records are provided for Ananteris cussinii Borelli 1910, Microtityus rickyi Kjellesvig-Waering 1966, Tityus clathratus C.L. Koch 1844 and Tityus melanostictus Pocock 1893. Specimens of Microtityus collected on Tobago provide evidence for the synonymy of Microtityus starri Lourenço & Huber 1999 with M. rickyi. Previously unreported ecological observations are presented, including the burrowing biology of Broteochactas laui Kjellesvig-Waering 1966, and the microhabitat of Chactas raymondhansorum Francke & Boos 1986, which is apparently not restricted to water-filled spaces between the leaf sheaths of bromeliads.

Recent phylogenetic studies of Opiliones have shown that Cyphophthalmi and Phalangida (= Palpatores Laniatores) are sister groups, but higher relationships within Phalangida remain controversial. Current debate focuses on whether Palpatores (= Caddoidea Phalangioidea Ischyropsalidoidea Troguloidea) is monophyletic or paraphyletic, with Ischyropsalidoidea Troguloidea (= Dyspnoi) being more closely related to Laniatores. The latter hypothesis was favored in recent combined studies of ribosomal DNA and morphology. Here higher relationships within Phalangida are examined using two nuclear protein-encoding genes, elongation factor-1α (EF-1α) and RNA polymerase II (Pol II), from 27 opilion species representing seven superfamilies. Cyphophthalmi was used as the outgroup. Nucleotide and inferred amino acid sequences were analyzed using maximum-parsimony and maximum-likelihood methods. All analyses recovered Palpatores as the monophyletic sister group to Laniatores with moderate to strong empirical support. Most palpatorean superfamilies were also recovered, but relationships among them were ambiguous or weakly supported. A monophyletic Palpatores was also obtained when EF-1α and Pol II sequences were analyzed together with 18S and 28S rDNA sequences.

We describe a new genus for a jumping spider that was originally placed in the large genus Menemerus Simon 1868, from which the new genus is clearly different. They were later reclassified as Icius, then as Pseudicius, and still later as Salticus. These initial classifications were repeated by a number of authors. The distinctive features of the male, and somewhat ambiguous features of the female, do not fit any known genus; and this species is here assigned to the new genus Hakka.

The African genus Palfuria Simon 1910 is revised. The genus now contains nine species: the type species Palfuria retusa Simon 1910, described on the base of single juvenile, P. gibbosa (Lessert 1936), P. panner Jocqué 1991, and six species that are described as new: P. caputlari (♂♀), P. harpago (♂), P. helichrysorum (♀), P. hirsuta (♀), P. gladiator (♂♀), P. spirembolus (♂♀). The male of Palfuria panner is redescribed, and the female described for the first time. Five species (P. retusa, P. spirembolus, P. gladiator, P. panner, P. harpago) are from the southwestern part of the continent, the other species (P. gibbosa, P. helichrysorum, P. hirsuta, P. caputlari) from the eastern part. The last species is from as far north as northern Tanzania. As in many other genera, there is a tendency for the embolus to increase in length. Both the most basal (Palfuria panner) and the most derived species (Palfuria spirembolus) are found in Namibia.

The fourth metatarsus of cribellate spiders bears a setal comb, the calamistrum, that sweeps over the cribellum, drawing fibrils from its spigots and helping to combine these with the capture thread's supporting fibers. In four uloborid species (Hyptiotes cavatus, Miagrammopes animotus, Octonoba sinensis, Uloborus glomosus), calamistrum length and cribellum width have similar developmental trajectories, despite being borne on different regions of the body. In contrast, developmental rates of metatarsus IV and its calamistrum differ within species and vary independently among species. Thus, the growth rates of metatarsus IV and the calamistrum are not coupled, freeing calamistrum length to track cribellum width and metatarsus IV length to respond to changes in such features as combing behavior and abdomen dimensions.

Differences in species richness and species composition of spiders associated with aquatic macrophytes of different structural complexities were examined in the Pantanal floodplain of Mato Grosso do Sul, Brazil. The plants studied were Nymphaea amazonum (Nymphaeaceae), Salvinia auriculata (Salviniaceae), Echinodorus paniculatus (Alismataceae) and Eichhornia azurea (Pontederiaceae), whose classes of complexity were determined based on their leaf and branch densities, vertical structure, and height. Data were collected from 62 monospecific plant patches in temporary lentic environments. A total of 235 spiders of 33 species in 13 families was collected. Nymphaea amazonum, the plant with the lowest complexity class, did not provide adequate sites for the establishment of spiders, and only four individuals of four spider species were found on its patches. Salvinia auriculata and E. paniculatus shared the intermediate class of complexity, but showed statistically significant differences in composition and richness of spider species. In E. paniculatus, greater height and lower leaf and branch densities favored the establishment of web weavers, whereas the smaller height and higher density of S. auriculata promoted the occurrence of wandering spiders. Eichhornia azurea, the plant with the highest complexity class, presented the greatest number of unique spider species, differing from the other plants in spider species composition. Results indicate that richness and composition of spider species associated with aquatic macrophytes in the study site are influenced by the structural complexity of these plants.

Argyrodes fictilium is a rarely collected species whose northern range was thought to be southern Canada. Recent collections in the eastern boreal forests of Québec extend its distribution range to the north and suggest that A. fictilium might be found anywhere within the boreal forest tree limit. Mature males collected in May indicate a summer-stenochronous type of phenology.

After producing a cylindrical egg sac, a female Miagrammopes animotus holds it until spiderlings emerge and disperse. When sacs were taken from females, these females exhibited a putative searching behavior and, upon contacting either their sacs or those of conspecifics, exhibited a putative recognition behavior. These responses would cause a female to search for and reclaim her sac if it were temporarily abandoned during feeding or web construction. Females with sacs did not respond positively to sacs from which spiderlings had emerged. Females that did not have sacs did not respond positively to viable sacs. Females separated from their sacs for increasing time periods exhibited a decline in positive responses to their sacs. Thus, contact with the sac appears necessary to maintain an affinity for the sac during the development of spiderlings.

The egg covering behavior of the laniatorid harvestman Promitobates ornatus was studied. Females of this species laid eggs isolated, on soil. After laying an egg, the female started scraping the substrate next to the egg, picking up debris, and attached the earth particles to the egg. After she scraped one area, she rotated around the egg, stopped turning, and restarted the collection of debris from another site. Alternation of scraping and changing body position was repeated twice or more until the female completed the egg covering. Data on egg size, duration of egg laying and egg covering, and duration of embryonic development are also provided.

Three species of sac spiders were reared under laboratory conditions to investigate their survival and development. First, the effects of three artificial diets, milk egg yolk, soybean liquid, and a combination of them, on the survival and development of Hibana velox were evaluated. Results over a 10 wk rearing period showed that the percentages of survival of H. velox reared on soybean liquid and combination diets did not differ significantly. However, the survival of H. velox on the milk egg yolk diet was significantly lower than on the other two artificial diets. More molts and instars occurred in spiders raised on milk egg yolk and on the combination diet than on the soybean liquid diet. Second, the development and percent survival of three sac spiders (Chiracanthium inclusum, H. velox, and Trachelas volutus) on artificial diet (i.e., the combination diet) and natural diets (i.e., citrus leafminer larvae and Drosophila adults) were compared. The three sac spiders developed into the adult stage on the combination diet. Similarly, all three sac spiders reared on Drosophila adults were able to develop to the adult stage. Chiracanthium inclusum and T. volutus reared on citrus leafminer larvae developed to the adult stage, whereas H. velox did not. Females of these three species that matured using combination diet and were fertilized in captivity produced 1–3 egg masses. Oviposition took place 2–7 days after mating. Chiracanthium inclusum had an average of 57 eggs per egg mass, whereas H. velox and T. volutus had an average of 110 and 56 eggs per egg mass, respectively.

An adult female Pardosa astrigera (Araneae, Lycosidae) died failing to finish an additional molt in the laboratory. Its maturity was morphologically ascertained by SEM examination.

The eggsac of the pirate spider, Mimetus notius, is described and compared with eggs of other members of the genus. The phorid fly egg predator, Phalacrotophora epeirae, was reared from a M. notius eggsac.

Aulonia bergi (Holmberg 1876) and Aulonia macrops Simon 1897 are considered nomina dubia. Agalenocosa luteonigra (Mello-Leitão 1945) new combination (= Aulonia luteonigra Mello-Leitão 1945) is illustrated. Glieschiella senex (Mello-Leitão 1945) is illustrated and synonymized under Allocosa brasiliensis (Petrunkevitch 1910).

Harvestmen Phalangium opilio regularly feed upon the carcasses of bees and moths discarded by crab spiders Misumena vatia Clerck 1757 hunting on flowers. I report one observation of a harvestman unsuccessfully attempting to secure a bee still being fed on by a crab spider.

The difference in activity levels between adult male and female spiders has been attributed to a more sexually motivated searching behavior by males, but the possibility that females reduce their activity when they reach maturity has not been considered, which may be evaluated by comparing adults and late instar juveniles behavior. We recorded the displacements during 15 min periods for 137 males, females and juveniles of Ctenus amphora and C. crulsi, two similar-sized syntopic hunting spiders species which search for prey on the leaf litter in central Amazonian tropical rainforests. For both species, males were significantly more active than females and juveniles. Ctenus amphora females were less active than juveniles, but the C. crulsi female activity did not differ from the juvenile activity. There were no significant differences in activity between these species for males and females, but the juveniles of C. amphora where more active than the juveniles of C. crulsi. Therefore, differences in activity between sexes are not always restricted to changes in male behavior, and the degree of decrease in female activity may depend on how active juveniles are.