The spider Homalonychus theologus is endemic to desert zones from southwestern California to southern Baja California Peninsula. Until now little has been published about its biology. In this paper we describe the reproductive and self-burying behavior and some aspects of the ecology of the species. Courtship behavior is between levels I and II, and the copulation position is a modification of type III. The male wraps the female's legs in silk before mating. This behavior could help justify inclusion of the Homalonychidae in the superfamily Lycosoidea. Possible camouflage behavior was attributed to the observation that these spiders can camouflage themselves by adhered sand grains to their bodies and buried themselves in the substratum. Females constructed eggsacs two days on average after mating one eggsac contained 29 eggs and other zero. Females incorporated sand "collars" to the egg sac with silk, probably as protection for the eggs against the dry environment as well as camouflage. This activity was carried out within 34 hours before oviposition. In the field, solitary spiders were found mainly under dead fallen cacti Pachycereus pringlei.RESUMEN. La arana Homalonychus theologus es endemica de las zonas deserticas del sur de California hasta el sur de la peninsula de Baja California. Hasta ahora se conoce poco acerca de su biologia. En este articulo describimos los habitos reproductores, conducta de enterramiento y aportamos algunos datos ecologicos de esta especie. La conducta de cortejo es intermedia entre los niveles I y II y la posicion de copula corresponde a una modificacion del tipo III. El macho envuelve las patas de la hembra con seda antes de la copula. Esta conducta puede contribuir a que las Homalonychidae puedan ser incluidas en la Superfamilia Lycosoidea. La posible conducta de enterramiento fue registrada cuando las aranas incorporaron granos de arena a sus cuerpos y se enterraron en el sustrato. Las hembras fabricae sus ovisacos pocos dias despues del apareamiento con un promedio de dos dias en su elaboracion y el numero de huevos observado fue de 0-29 por ovisaco. Las hembras incorporan "collares" de arena con seda al ovisaco como una probable proteccion de los huevos a la desecacion del medio. Este evento fue llevado a cabo en 34 horas. En el campo, las aranas se encontraron principalmente solas y bajo cardones en descomposicion Pachycereus pringlei.

Infection rates of Trypanosoma cruzi Chagas (in the blood-sucking bug Dipetalogaster maximus [Uhler]) were determined from specimens collected at 12 localities in the Cape Region of Baja California Sur, Mexico. Eight collection sites were located in the tropical dry forest, two in desert shrub, and two in the ecotone between these two communities. Of the 245 D. maximus collected, 65% were first and second instar nymphs; 32.6% were third, fourth, and fifth instar nymphs; and 2.4% were adults. The highest proportion of specimens came from El Fandango (30%) and San Bartolo (23%) canyons and La Cruz hill (12%) in the mountain slopes facing the Gulf of California. In feces from individual bugs analyzed for T. cruzi, we found an overall infection rate of 7.0%. Infection rates increased from 4.1% in second instars to 42.% in fifth instars. High infection rates were found in bugs collected from La Poza (38.4%), El Gato (27.2%), and El Pedregoso (25%) hills; low infection rates were found in specimens from La Cruz hill and San Bartolo canyon. Specimens from some collection sites were not infected with T. cruzi.

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Se proporciona una lista con 77 especies de arañas del Área Natural Protegida (ANP) Médanos de Samalayuca, agrupadas en 51 géneros y 21 familias. Las familias con mayor número de especies fueron Salticidae, Thomisidae, Gnaphosidae y Philodromidae. También se aportan cinco nuevos registros de especies de arañas para la República Mexicana y ocho para el Estado de Chihuahua. El matorral desértico micrófilo agrupó a 16 familias 27 géneros 31 especies y de la vegetación del desierto arenoso se registraron 15 familias, 28 géneros y 37 especies, compartiendo 17 familias, 36 géneros y 46 especies, con una complementariedad del 84%. En el estrato de vegetación se registraron 13 familias 43 especies y en el suelo 11 familias y 31 especies, compartiendo tres especies, con una complementariedad del 95%.