The drumming signals of seven California stonefly species from the family Perlodidae are reported. Drumming descriptions are improved by graphing each of the signal's individual intervals (or interval pattern) and the determination of signal type (monophasic, varied beat-interval, diphasic and grouped) is based upon these graphs. Signals are described for the first time for two species: Baumanella alameda (Needham & Claassen) and Cultus pilatus (Frison). New signal characters and signals from additional locations are provided for five species: Calliperla luctuosa (Banks), Chernokrilus misnomus (Claassen), Cosumnoperla hypocrena Szczytko & Bottorff, Osobenus yakimae (Hoppe), and Rickera sorpta (Needham & Claassen).

Tardigrades were collected from 73 urban sites and 24 rural locations in Fresno County, California to determine if differences existed in community structure between the two environments. Only 22 percent of urban samples were positive for tardigrades, as compared to 74 percent of rural samples. Samples from urban sites contained significantly fewer species than rural sites, although the average density did not vary significantly between urban and rural sites. Twenty-six different species were identified, with seven exclusively in the urban samples, 16 found only from rural samples, and three species found in both environments. Similarity analysis indicated urban communities were more similar to one another compared to similarities among rural communities, indicating significant differences between urban and rural communities. Tardigrades appeared to prefer habitat with a lower pH in both urban and rural locations. While our findings do support the negative relationship between urban sites and tardigrade richness, it was not explained by the lower pH typically associated with urban habitats. Further, we identified two species of Isohypsibius not previously recorded in the Western Hemisphere. The genus Eremobiotus was found for the first time in the Americas, and a species of Ramazzottius for the first time in North America.

A list of the world species of Ephedrus is given, including 43 species from the Afrotropical, Australasian, Nearctic, Oriental and Palearctic Regions, including synonyms and distributions. Ephedrus ramnagarensis sp. nov. Akhtar is described from Ghatti, Ramnagar, Uttarakhand, India.

Two new species of the genus Thitarodes, T. sejilaensis sp. nov. and T. jiachaensis sp. nov., from Tibet in China are described and illustrated. All specimens are deposited in the Biological Museum of Sun Yat-sen University, Guangzhou, China.

Discrete external morphology mediated by host plant substrate is reported for the first time as an alternative phenotype in the larval stages of the psylloid Calophya californica Schwarz (Calophyidae). These polymorphs are believed to be the first observations of host mediated polyphenism in larval stages within the Psylloidea. The habitus and morphology of a previously unrecognized leaf form of the larval stages of C. californica is described and fruit limited generations are reported for the first time on the host plant Rhus integrifolia (Nutt.) Brewer & S. Watson (Anacardiaceae). The adaptive morphology of leaf, fruit and stem forms of the same species occurring among sister groups within the Sternorrhyncha is discussed.

Medetera johnthomasi (Diptera: Dolichopodidae) is described from a large population collected in San Mateo County, California. This is the third Nearctic species in the Medetera aberrans species group, a lineage that otherwise is pan-tropical in distribution, but particularly diverse in the Neotropical region. Males of most species in this species group have the tarsomeres 2–4 of leg I flattened. The position of this species group within Medetera is discussed.